Here, I review the development of a polysilicon photonic platform that is optimized for integration with electronics fabricated on bulk silicon wafers. This platform enables large-scale monolithic integration of silicon photonics with microelectronics. A single-polysilicon deposition and lithography mask were used to simultaneously define the transistor gate, the low-loss waveguides, the depletion modulators, and the photodetectors. Several approaches to reduce optical scattering and mitigate defect state absorption are presented. Waveguide propagation loss as low as 3 dB/cm could be realized in front-end polysilicon with an end-of-line loss as low as 10 dB/cm at 1280nm. The defect state density could be enhanced to enable all-silicon, infrared photodetectors. The resulting microring resonant detectors exhibit over 20% quantum efficiency with 9.7 GHz bandwidth over a wide range of wavelengths. A complete photonic link has been demonstrated at 5 Gbps that transfers digital information from one bulk CMOS photonics chip to another.
{"title":"Photonic-electronic integration with polysilicon photonics in bulk CMOS","authors":"Rajeev J Ram","doi":"10.1117/12.2175462","DOIUrl":"https://doi.org/10.1117/12.2175462","url":null,"abstract":"Here, I review the development of a polysilicon photonic platform that is optimized for integration with electronics fabricated on bulk silicon wafers. This platform enables large-scale monolithic integration of silicon photonics with microelectronics. A single-polysilicon deposition and lithography mask were used to simultaneously define the transistor gate, the low-loss waveguides, the depletion modulators, and the photodetectors. Several approaches to reduce optical scattering and mitigate defect state absorption are presented. Waveguide propagation loss as low as 3 dB/cm could be realized in front-end polysilicon with an end-of-line loss as low as 10 dB/cm at 1280nm. The defect state density could be enhanced to enable all-silicon, infrared photodetectors. The resulting microring resonant detectors exhibit over 20% quantum efficiency with 9.7 GHz bandwidth over a wide range of wavelengths. A complete photonic link has been demonstrated at 5 Gbps that transfers digital information from one bulk CMOS photonics chip to another.","PeriodicalId":432115,"journal":{"name":"Photonics West - Optoelectronic Materials and Devices","volume":"25 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2015-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125954648","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
M. Popović, M. Wade, J. Orcutt, J. Shainline, Chen Sun, M. Georgas, B. Moss, R. Kumar, L. Alloatti, F. Pavanello, Yu-hsin Chen, Kareem Nammari, J. Notaros, A. Atabaki, J. Leu, V. Stojanović, Rajeev J Ram
We review recent progress of an effort led by the Stojanović (UC Berkeley), Ram (MIT) and Popović (CU Boulder) research groups to enable the design of photonic devices, and complete on-chip electro-optic systems and interfaces, directly in standard microelectronics CMOS processes in a microprocessor foundry, with no in-foundry process modifications. This approach allows tight and large-scale monolithic integration of silicon photonics with state-of-the-art (sub-100nm-node) microelectronics, here a 45nm SOI CMOS process. It enables natural scale-up to manufacturing, and rapid advances in device design due to process repeatability. The initial driver application was addressing the processor-to-memory communication energy bottleneck. Device results include 5Gbps modulators based on an interleaved junction that take advantage of the high resolution of the sub-100nm CMOS process. We demonstrate operation at 5fJ/bit with 1.5dB insertion loss and 8dB extinction ratio. We also demonstrate the first infrared detectors in a zero-change CMOS process, using absorption in transistor source/drain SiGe stressors. Subsystems described include the first monolithically integrated electronic-photonic transmitter on chip (modulator+driver) with 20-70fJ/bit wall plug energy/bit (2-3.5Gbps), to our knowledge the lowest transmitter energy demonstrated to date. We also demonstrate native-process infrared receivers at 220fJ/bit (5Gbps). These are encouraging signs for the prospects of monolithic electronics-photonics integration. Beyond processor-to-memory interconnects, our approach to photonics as a “More-than- Moore” technology inside advanced CMOS promises to enable VLSI electronic-photonic chip platforms tailored to a vast array of emerging applications, from optical and acoustic sensing, high-speed signal processing, RF and optical metrology and clocks, through to analog computation and quantum technology.
我们回顾了stojanovizi(加州大学伯克利分校)，Ram(麻省理工学院)和popovizi(科罗拉多大学博尔德分校)研究小组领导的一项研究的最新进展，该研究能够直接在微处理器代工厂的标准微电子CMOS工艺中设计光子器件，并完成片上电光系统和接口，而无需对代工厂工艺进行修改。这种方法允许硅光子学与最先进的(sub-100nm节点)微电子紧密和大规模的单片集成，这里是45nm SOI CMOS工艺。它可以自然地扩大生产规模，并且由于工艺可重复性，可以快速推进设备设计。最初的驱动程序应用程序解决了处理器到内存通信的能量瓶颈。器件结果包括基于交错结的5Gbps调制器，该调制器利用了亚100nm CMOS工艺的高分辨率。我们演示了5fJ/bit的操作，1.5dB插入损耗和8dB消光比。我们还展示了零变化CMOS工艺中的第一个红外探测器，在晶体管源/漏SiGe应力源中使用吸收。所描述的子系统包括第一个单片集成电子-光子片上发射器(调制器+驱动器)，具有20-70fJ/bit的壁插头能量/bit (2-3.5Gbps)，据我们所知，这是迄今为止展示的最低发射器能量。我们还演示了220fJ/bit (5Gbps)的本地处理红外接收器。对于单片电子-光子学集成的前景来说，这些都是令人鼓舞的迹象。除了处理器到存储器互连之外，我们的光子学方法作为先进CMOS内部的“超过摩尔”技术，有望使VLSI电子光子芯片平台适应大量新兴应用，从光学和声学传感，高速信号处理，射频和光学计量和时钟，到模拟计算和量子技术。
{"title":"Monolithic silicon photonics in a sub-100nm SOI CMOS microprocessor foundry: progress from devices to systems","authors":"M. Popović, M. Wade, J. Orcutt, J. Shainline, Chen Sun, M. Georgas, B. Moss, R. Kumar, L. Alloatti, F. Pavanello, Yu-hsin Chen, Kareem Nammari, J. Notaros, A. Atabaki, J. Leu, V. Stojanović, Rajeev J Ram","doi":"10.1117/12.2084604","DOIUrl":"https://doi.org/10.1117/12.2084604","url":null,"abstract":"We review recent progress of an effort led by the Stojanović (UC Berkeley), Ram (MIT) and Popović (CU Boulder) research groups to enable the design of photonic devices, and complete on-chip electro-optic systems and interfaces, directly in standard microelectronics CMOS processes in a microprocessor foundry, with no in-foundry process modifications. This approach allows tight and large-scale monolithic integration of silicon photonics with state-of-the-art (sub-100nm-node) microelectronics, here a 45nm SOI CMOS process. It enables natural scale-up to manufacturing, and rapid advances in device design due to process repeatability. The initial driver application was addressing the processor-to-memory communication energy bottleneck. Device results include 5Gbps modulators based on an interleaved junction that take advantage of the high resolution of the sub-100nm CMOS process. We demonstrate operation at 5fJ/bit with 1.5dB insertion loss and 8dB extinction ratio. We also demonstrate the first infrared detectors in a zero-change CMOS process, using absorption in transistor source/drain SiGe stressors. Subsystems described include the first monolithically integrated electronic-photonic transmitter on chip (modulator+driver) with 20-70fJ/bit wall plug energy/bit (2-3.5Gbps), to our knowledge the lowest transmitter energy demonstrated to date. We also demonstrate native-process infrared receivers at 220fJ/bit (5Gbps). These are encouraging signs for the prospects of monolithic electronics-photonics integration. Beyond processor-to-memory interconnects, our approach to photonics as a “More-than- Moore” technology inside advanced CMOS promises to enable VLSI electronic-photonic chip platforms tailored to a vast array of emerging applications, from optical and acoustic sensing, high-speed signal processing, RF and optical metrology and clocks, through to analog computation and quantum technology.","PeriodicalId":432115,"journal":{"name":"Photonics West - Optoelectronic Materials and Devices","volume":"96 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2015-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131909773","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Sub-wavelength high contrast gratings offer the exciting possibility of “membrane-in-the-middle” optomechanics with a low-mass, highly reflective membrane. Theoretical treatments of this system have, to date, employed the model of a zero-thickness polarizable slab. The validity of this model is, however, limited, since in general highly reflective subwavelength gratings do not have an optical thickness that is much smaller than the wavelength of the light employed. In this work, we show that this model in fact makes incorrect predictions concerning the field modes in an optical cavity with a subwavelength grating at the exact center. It predicts that the modes can be classified in doublets, one member of which has an antisymmetric spatial profile and no absorption, the other of which has a symmetric spatial profile and absorptive losses. The situation for a subwavelength grating, however, is quite different: Both modes have absorptive loss, but the mode with the antisymmetric spatial profile has greater loss. In addition, the frequencies of the modes are interchanged: In the case of the zero-thickness slab, the antisymmetric mode has the lower frequency, while in the case of the subwavelength grating, it is the symmetric mode that is the low-frequency member of the doublet. These considerations will be important for a correct interpretation of experimental data as the performance of such sytems continues to improve.
{"title":"Membrane-in-the-middle optomechanics with high-contrast gratings","authors":"J. Lawall","doi":"10.1117/12.2086170","DOIUrl":"https://doi.org/10.1117/12.2086170","url":null,"abstract":"Sub-wavelength high contrast gratings offer the exciting possibility of “membrane-in-the-middle” optomechanics with a low-mass, highly reflective membrane. Theoretical treatments of this system have, to date, employed the model of a zero-thickness polarizable slab. The validity of this model is, however, limited, since in general highly reflective subwavelength gratings do not have an optical thickness that is much smaller than the wavelength of the light employed. In this work, we show that this model in fact makes incorrect predictions concerning the field modes in an optical cavity with a subwavelength grating at the exact center. It predicts that the modes can be classified in doublets, one member of which has an antisymmetric spatial profile and no absorption, the other of which has a symmetric spatial profile and absorptive losses. The situation for a subwavelength grating, however, is quite different: Both modes have absorptive loss, but the mode with the antisymmetric spatial profile has greater loss. In addition, the frequencies of the modes are interchanged: In the case of the zero-thickness slab, the antisymmetric mode has the lower frequency, while in the case of the subwavelength grating, it is the symmetric mode that is the low-frequency member of the doublet. These considerations will be important for a correct interpretation of experimental data as the performance of such sytems continues to improve.","PeriodicalId":432115,"journal":{"name":"Photonics West - Optoelectronic Materials and Devices","volume":"2014 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2015-03-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127533267","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Contrary to common belief, light does not all the time propagate linearly. Hence it tends to bend when it takes the form of airy wave packets. This paper describes a first possible application of such wave packets to automotive lighting technology. After a first brief description of the historical background of the airy beams principle and their potential applications, a detailed analysis of these beams under potential-free Schrödinger equation with physical formulations is proposed. Considering that one of the most peculiar characteristic of airy waves is that they stay diffraction free when propagating, ‘diffraction’ and ‘diffraction-free propagation’ aspects and the physics behind it is then analyzed and described at the second step. In the third part of the paper, the characteristics of Bessel Beams, and their diffraction free behavior is explored and a comparison between Bessel beams and Airy beams is crosschecked. As Airy beams do accelerate during propagation, they describe a ballistic trajectory and bend. Up to now, these beams were mainly used to generate curved plasma channels in air and for particle separation in optical trapping applications. We investigate in our paper how the bending property of Airy beams could be used to achieve illumination in curved roads and corners in an automotive lighting application. Considering that so far, Airy beams were never thought to be a possible alternative to the current mechanical systems used to provide a “bending light” function, we describe how this could be achieved and what are the next steps to be investigated.
{"title":"Airy wave packets and their application to automotive lighting","authors":"Ceren Altıngöz","doi":"10.1117/12.2078359","DOIUrl":"https://doi.org/10.1117/12.2078359","url":null,"abstract":"Contrary to common belief, light does not all the time propagate linearly. Hence it tends to bend when it takes the form of airy wave packets. This paper describes a first possible application of such wave packets to automotive lighting technology. After a first brief description of the historical background of the airy beams principle and their potential applications, a detailed analysis of these beams under potential-free Schrödinger equation with physical formulations is proposed. Considering that one of the most peculiar characteristic of airy waves is that they stay diffraction free when propagating, ‘diffraction’ and ‘diffraction-free propagation’ aspects and the physics behind it is then analyzed and described at the second step. In the third part of the paper, the characteristics of Bessel Beams, and their diffraction free behavior is explored and a comparison between Bessel beams and Airy beams is crosschecked. As Airy beams do accelerate during propagation, they describe a ballistic trajectory and bend. Up to now, these beams were mainly used to generate curved plasma channels in air and for particle separation in optical trapping applications. We investigate in our paper how the bending property of Airy beams could be used to achieve illumination in curved roads and corners in an automotive lighting application. Considering that so far, Airy beams were never thought to be a possible alternative to the current mechanical systems used to provide a “bending light” function, we describe how this could be achieved and what are the next steps to be investigated.","PeriodicalId":432115,"journal":{"name":"Photonics West - Optoelectronic Materials and Devices","volume":"42 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2015-03-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116464724","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
C. Blanchard, C. Jamois, P. Viktorovitch, C. Grillet, J. Leclercq, T. Benyattou, X. Letartre
The comprehension and manipulation of the spectral characteristics of photonic structures is of great interest for a vast bunch of applications, in particular for energy efficiency. In this paper we focus on a perturbation model capable of providing insight and control on the resonances that are supported by high index contrast gratings.
{"title":"Perturbation model for the control of the spectral properties of high contrast gratings","authors":"C. Blanchard, C. Jamois, P. Viktorovitch, C. Grillet, J. Leclercq, T. Benyattou, X. Letartre","doi":"10.1117/12.2076595","DOIUrl":"https://doi.org/10.1117/12.2076595","url":null,"abstract":"The comprehension and manipulation of the spectral characteristics of photonic structures is of great interest for a vast bunch of applications, in particular for energy efficiency. In this paper we focus on a perturbation model capable of providing insight and control on the resonances that are supported by high index contrast gratings.","PeriodicalId":432115,"journal":{"name":"Photonics West - Optoelectronic Materials and Devices","volume":"9372 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2015-03-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130501243","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
We review a new type of dispersion elements based on a Bragg reflector waveguide, which provides a large angular dispersion of 1~2°/nm. The device functions as sub-wavelength virtually imaged phased array grating. We obtain a number of resolution-points (possible channel-count in demultiplexing) over 1,000. We demonstrate a large-scale wavelength switch based on a Bragg reflector waveguides array. The waveguides array has a small footprint of 2×4 mm2, but provides both ultra-large numbers (>100) of output-ports and wavelength-channels at the same time. Prospects for further increase in the wavelength channel count and output ports will be discussed.
{"title":"Virtually image phased array based on Bragg reflector waveguide for large-port optical switching","authors":"F. Koyama","doi":"10.1117/12.2084908","DOIUrl":"https://doi.org/10.1117/12.2084908","url":null,"abstract":"We review a new type of dispersion elements based on a Bragg reflector waveguide, which provides a large angular dispersion of 1~2°/nm. The device functions as sub-wavelength virtually imaged phased array grating. We obtain a number of resolution-points (possible channel-count in demultiplexing) over 1,000. We demonstrate a large-scale wavelength switch based on a Bragg reflector waveguides array. The waveguides array has a small footprint of 2×4 mm2, but provides both ultra-large numbers (>100) of output-ports and wavelength-channels at the same time. Prospects for further increase in the wavelength channel count and output ports will be discussed.","PeriodicalId":432115,"journal":{"name":"Photonics West - Optoelectronic Materials and Devices","volume":"9372 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2015-03-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130946497","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
T. Sandner, C. Baulig, T. Grasshoff, M. Wildenhain, M. Schwarzenberg, Hans-Georg Dahlmann, S. Schwarzer
This paper presents a large aperture micro scanning mirror (MSM) array especially developed for the novel 3D-laser camera Fovea3D. This 3D-camera uses a pulsed ToF technique with 1MVoxel distance measuring rate and targets for a large measurement range of 30…100m and FOV of 120°x60° at video like frame rates. To guarantee a large reception aperture of ≥ 20mm, large FOV and 3200 Hz bi-directional scanning frequency at the same time, a hybrid assembled MSM array was developed consisting of 22 reception mirrors and a separate sending mirror. A hybrid assembly of frequency selected scanner elements and a driving in parametric resonance were chosen to enable a fully synchronized operation of all scanner elements. For position feedback piezo-resistive position sensors are integrated on each MEMS chip. The paper discusses details of the MEMS system integration including the synchronized operation of multiple scanning elements.
{"title":"Hybrid assembled micro scanner array with large aperture and their system integration for a 3D ToF laser camera","authors":"T. Sandner, C. Baulig, T. Grasshoff, M. Wildenhain, M. Schwarzenberg, Hans-Georg Dahlmann, S. Schwarzer","doi":"10.1117/12.2076440","DOIUrl":"https://doi.org/10.1117/12.2076440","url":null,"abstract":"This paper presents a large aperture micro scanning mirror (MSM) array especially developed for the novel 3D-laser camera Fovea3D. This 3D-camera uses a pulsed ToF technique with 1MVoxel distance measuring rate and targets for a large measurement range of 30…100m and FOV of 120°x60° at video like frame rates. To guarantee a large reception aperture of ≥ 20mm, large FOV and 3200 Hz bi-directional scanning frequency at the same time, a hybrid assembled MSM array was developed consisting of 22 reception mirrors and a separate sending mirror. A hybrid assembly of frequency selected scanner elements and a driving in parametric resonance were chosen to enable a fully synchronized operation of all scanner elements. For position feedback piezo-resistive position sensors are integrated on each MEMS chip. The paper discusses details of the MEMS system integration including the synchronized operation of multiple scanning elements.","PeriodicalId":432115,"journal":{"name":"Photonics West - Optoelectronic Materials and Devices","volume":"41 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2015-03-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115928810","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Nanoimprinting techniques are an attractive solution for next generation lithography methods for several areas including photonic devices. A variety of potential applications have been demonstrated using nanoimprint lithography (NIL) (e.g. SAW devices, vias and contact layers with dual damascene imprinting process, Bragg structures, patterned media) [1,2]. Nanoimprint lithography is considered for bridging the gap from R and D to high volume manufacturing. In addition, it is capable to adapt to the needs of the fragmented and less standardized photonic market easily. In this work UV-NIL has been selected for the fabrication process of 3D-photonic crystals. It has been shown that UVNIL using a multiple layer approach is well suited to fabricate a 3D woodpile photonic crystal. The necessary alignment accuracies below 100nm were achieved using a simple optical method. In order to obtain sufficient alignment of the stacks to each other, a two stage alignment process is performed: at first proximity alignment is done followed by the Moire´ alignment in soft contact with the substrate. Multiple steps of imprinting, etching, Si deposition and chemical mechanical polishing were implemented to create high quality 3D photonic crystals with up to 5 layers. This work has proven the applicability of nanoimprint lithography in a CMOS compatible process on 3D photonic crystals with alignment accuracy down to 100nm. Optimizing the processes will allow scaling up these structures on full wafers while still meeting the requirements of the designated devices.
{"title":"CMOS compatible fabrication of 3D photonic crystals by nanoimprint lithography","authors":"M. Eibelhuber, T. Uhrmann, T. Glinsner","doi":"10.1117/12.2084583","DOIUrl":"https://doi.org/10.1117/12.2084583","url":null,"abstract":"Nanoimprinting techniques are an attractive solution for next generation lithography methods for several areas including photonic devices. A variety of potential applications have been demonstrated using nanoimprint lithography (NIL) (e.g. SAW devices, vias and contact layers with dual damascene imprinting process, Bragg structures, patterned media) [1,2]. Nanoimprint lithography is considered for bridging the gap from R and D to high volume manufacturing. In addition, it is capable to adapt to the needs of the fragmented and less standardized photonic market easily. In this work UV-NIL has been selected for the fabrication process of 3D-photonic crystals. It has been shown that UVNIL using a multiple layer approach is well suited to fabricate a 3D woodpile photonic crystal. The necessary alignment accuracies below 100nm were achieved using a simple optical method. In order to obtain sufficient alignment of the stacks to each other, a two stage alignment process is performed: at first proximity alignment is done followed by the Moire´ alignment in soft contact with the substrate. Multiple steps of imprinting, etching, Si deposition and chemical mechanical polishing were implemented to create high quality 3D photonic crystals with up to 5 layers. This work has proven the applicability of nanoimprint lithography in a CMOS compatible process on 3D photonic crystals with alignment accuracy down to 100nm. Optimizing the processes will allow scaling up these structures on full wafers while still meeting the requirements of the designated devices.","PeriodicalId":432115,"journal":{"name":"Photonics West - Optoelectronic Materials and Devices","volume":"27 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2015-03-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133256693","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
D. Rogers, S. Sundaram, Y. El Gmili, F. Teherani, P. Bove, V. Sandana, P. Voss, A. Ougazzaden, A. Rajan, K. Prior, R. Mcclintock, M. Razeghi
(In)GaN p-i-n structures were grown by MOVPE on both GaN- and ZnO-coated c-sapphire substrates. XRD studies of the as-grown layers revealed that a strongly c-axis oriented wurtzite crystal structure was obtained on both templates and that there was a slight compressive strain in the ZnO underlayer which increased after GaN overgrowth. The InGaN peak position gave an estimate of 13.6at% for the indium content in the active layer. SEM and AFM revealed that the top surface morphologies were similar for both substrates, with an RMS roughness (5 μm x 5 μm) of about 10 nm. Granularity appeared slightly coarser (40nm for the device grown on ZnO vs 30nm for the device grown on the GaN template) however. CL revealed a weaker GaN near band edge UV emission peak and a stronger broad defect-related visible emission band for the structure grown on the GaN template. Only a strong ZnO NBE UV emission was observed for the sample grown on the ZnO template. Quarter-wafer chemical lift-off (CLO) of the InGaN-based p-i-n structures from the sapphire substrate was achieved by temporary-bonding the GaN surface to rigid glass support with wax and then selectively dissolving the ZnO in 0.1M HCl. XRD studies revealed that the epitaxial nature and strong preferential c-axis orientation of the layers had been maintained after lift-off. This demonstration of CLO scale-up, without compromising the crystallographic integrity of the (In)GaN p-i-n structure opens up the perspective of transferring GaN based devices off of sapphire substrates industrially.
{"title":"Scale-up of the chemical lift-off of (In)GaN-based p-i-n junctions from sapphire substrates using sacrificial ZnO template layers","authors":"D. Rogers, S. Sundaram, Y. El Gmili, F. Teherani, P. Bove, V. Sandana, P. Voss, A. Ougazzaden, A. Rajan, K. Prior, R. Mcclintock, M. Razeghi","doi":"10.1117/12.2175897","DOIUrl":"https://doi.org/10.1117/12.2175897","url":null,"abstract":"(In)GaN p-i-n structures were grown by MOVPE on both GaN- and ZnO-coated c-sapphire substrates. XRD studies of the as-grown layers revealed that a strongly c-axis oriented wurtzite crystal structure was obtained on both templates and that there was a slight compressive strain in the ZnO underlayer which increased after GaN overgrowth. The InGaN peak position gave an estimate of 13.6at% for the indium content in the active layer. SEM and AFM revealed that the top surface morphologies were similar for both substrates, with an RMS roughness (5 μm x 5 μm) of about 10 nm. Granularity appeared slightly coarser (40nm for the device grown on ZnO vs 30nm for the device grown on the GaN template) however. CL revealed a weaker GaN near band edge UV emission peak and a stronger broad defect-related visible emission band for the structure grown on the GaN template. Only a strong ZnO NBE UV emission was observed for the sample grown on the ZnO template. Quarter-wafer chemical lift-off (CLO) of the InGaN-based p-i-n structures from the sapphire substrate was achieved by temporary-bonding the GaN surface to rigid glass support with wax and then selectively dissolving the ZnO in 0.1M HCl. XRD studies revealed that the epitaxial nature and strong preferential c-axis orientation of the layers had been maintained after lift-off. This demonstration of CLO scale-up, without compromising the crystallographic integrity of the (In)GaN p-i-n structure opens up the perspective of transferring GaN based devices off of sapphire substrates industrially.","PeriodicalId":432115,"journal":{"name":"Photonics West - Optoelectronic Materials and Devices","volume":"30 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2015-03-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125109297","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
V. Sandana, D. Rogers, F. Hosseini Teherani, P. Bove, N. Ben Sedrine, M. Correia, T. Monteiro, R. Mcclintock, M. Razeghi
NiO/ZnO heterostructures were fabricated on FTO/glass and bulk hydrothermal ZnO substrates by pulsed laser deposition. X-Ray diffraction and Room Temperature (RT) Raman studies were consistent with the formation of (0002) oriented wurtzite ZnO and (111) oriented fcc NiO. RT optical transmission studies revealed bandgap energy values of ~3.70 eV and ~3.30 eV for NiO and ZnO, respectively and more than 80% transmission for the whole ZnO/NiO/FTO/glass stack over the majority of the visible spectrum. Lateral p-n heterojunction mesas (~6mm x 6mm) were fabricated using a shadow mask during PLD growth. n-n and p-p measurements showed that Ti/Au contacting gave an Ohmic reponse for the NiO, ZnO and FTO. Both heterojunctions had rectifying I/V characteristics. The junction on FTO/glass gave forward bias currents (243mA at +10V) that were over 5 orders of magnitude higher than those for the junction formed on bulk ZnO. At ~ 10-7 A (for 10V of reverse bias) the heterojunction leakage current was approximately two orders of magnitude lower on the bulk ZnO substrate than on FTO. Overall, the lateral p-NiO/n- ZnO/FTO/glass device proved far superior to that formed by growing p-NiO directly on the bulk n-ZnO substrate and gave a combination of electrical performance and visible wavelength transparency that could predispose it for use in various third generation transparent electronics applications.
采用脉冲激光沉积技术在FTO/玻璃和体水热ZnO衬底上制备了NiO/ZnO异质结构。x射线衍射和室温(RT)拉曼研究结果与(0002)取向纤锌矿ZnO和(111)取向fcc NiO的形成一致。RT光传输研究表明，NiO和ZnO的带隙能值分别为~3.70 eV和~3.30 eV，整个ZnO/NiO/FTO/玻璃堆在大部分可见光谱上的透射率超过80%。在PLD生长过程中使用阴影掩膜制备了横向p-n异质结台面(~6mm x 6mm)。n-n和p-p测量表明，Ti/Au接触对NiO、ZnO和FTO产生欧姆响应。两种异质结均具有整流I/V特性。FTO/玻璃上结的正向偏置电流(+10V时为243mA)比ZnO上结的正向偏置电流高出5个数量级以上。在~ 10-7 A时(10V的反向偏置)，ZnO衬底上的异质结漏电流比FTO上的低约两个数量级。总体而言，横向p-NiO/n- ZnO/FTO/玻璃器件被证明远远优于直接在大块n-ZnO衬底上生长p-NiO形成的器件，并且具有电性能和可见波长透明度的组合，可以使其易于用于各种第三代透明电子应用。
{"title":"Structural, optical, electrical and morphological study of transparent p-NiO/n-ZnO heterojunctions grown by PLD","authors":"V. Sandana, D. Rogers, F. Hosseini Teherani, P. Bove, N. Ben Sedrine, M. Correia, T. Monteiro, R. Mcclintock, M. Razeghi","doi":"10.1117/12.2177427","DOIUrl":"https://doi.org/10.1117/12.2177427","url":null,"abstract":"NiO/ZnO heterostructures were fabricated on FTO/glass and bulk hydrothermal ZnO substrates by pulsed laser deposition. X-Ray diffraction and Room Temperature (RT) Raman studies were consistent with the formation of (0002) oriented wurtzite ZnO and (111) oriented fcc NiO. RT optical transmission studies revealed bandgap energy values of ~3.70 eV and ~3.30 eV for NiO and ZnO, respectively and more than 80% transmission for the whole ZnO/NiO/FTO/glass stack over the majority of the visible spectrum. Lateral p-n heterojunction mesas (~6mm x 6mm) were fabricated using a shadow mask during PLD growth. n-n and p-p measurements showed that Ti/Au contacting gave an Ohmic reponse for the NiO, ZnO and FTO. Both heterojunctions had rectifying I/V characteristics. The junction on FTO/glass gave forward bias currents (243mA at +10V) that were over 5 orders of magnitude higher than those for the junction formed on bulk ZnO. At ~ 10-7 A (for 10V of reverse bias) the heterojunction leakage current was approximately two orders of magnitude lower on the bulk ZnO substrate than on FTO. Overall, the lateral p-NiO/n- ZnO/FTO/glass device proved far superior to that formed by growing p-NiO directly on the bulk n-ZnO substrate and gave a combination of electrical performance and visible wavelength transparency that could predispose it for use in various third generation transparent electronics applications.","PeriodicalId":432115,"journal":{"name":"Photonics West - Optoelectronic Materials and Devices","volume":"6 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2015-03-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124646641","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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