Pub Date : 1998-12-14DOI: 10.1109/COMMAD.1998.791615
I. Hosako, K. Okumura, M. Akiba, N. Hiromoto
This paper examines InGaAs-channel heterojunction-FETs (HJ-FETs) and GaAs-JFETs for their low-noise and low-power characteristics at 4.2 K. We demonstrated that Hooge's empirical relation applies to a FET with long gate.
{"title":"Characterization of low frequency noise in InGaAs-channel heterojunction-FET's and GaAs-JFET's at liquid helium temperature","authors":"I. Hosako, K. Okumura, M. Akiba, N. Hiromoto","doi":"10.1109/COMMAD.1998.791615","DOIUrl":"https://doi.org/10.1109/COMMAD.1998.791615","url":null,"abstract":"This paper examines InGaAs-channel heterojunction-FETs (HJ-FETs) and GaAs-JFETs for their low-noise and low-power characteristics at 4.2 K. We demonstrated that Hooge's empirical relation applies to a FET with long gate.","PeriodicalId":300064,"journal":{"name":"1998 Conference on Optoelectronic and Microelectronic Materials and Devices. Proceedings (Cat. No.98EX140)","volume":"417 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1998-12-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124256525","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}
Pub Date : 1998-12-14DOI: 10.1109/COMMAD.1998.791601
T. Green, W. Xu
An optically pumped far-infrared (FIR) intersubband laser generator is proposed in which the continuum states above an Al/sub 0.2/Ga/sub 0.8/As-GaAs-Al/sub 0.2/Ga/sub 0.8/As single quantum well structure with a well width of L=170 /spl Aring/ serve as the highest level in a four-level laser system. This simple structure has been designed to take advantage of the electro-phonon resonance (EPR) effect induced by electron interactions with longitudinal optical (LO) phonons in GaAs-based two-dimensional semiconductor systems (2DSSs), in achieving population inversion between the second and third electronic subbands. The design allows much greater flexibility in the choice of pumping sources and simplifies considerably the device fabrication. The electronic subband structure of the proposed FIR intersubband laser device has been obtained from a self-consistent calculation via solving coupled Schrodinger and Poisson equations.
{"title":"Far-infrared laser generation from an optically pumped single quantum well structure","authors":"T. Green, W. Xu","doi":"10.1109/COMMAD.1998.791601","DOIUrl":"https://doi.org/10.1109/COMMAD.1998.791601","url":null,"abstract":"An optically pumped far-infrared (FIR) intersubband laser generator is proposed in which the continuum states above an Al/sub 0.2/Ga/sub 0.8/As-GaAs-Al/sub 0.2/Ga/sub 0.8/As single quantum well structure with a well width of L=170 /spl Aring/ serve as the highest level in a four-level laser system. This simple structure has been designed to take advantage of the electro-phonon resonance (EPR) effect induced by electron interactions with longitudinal optical (LO) phonons in GaAs-based two-dimensional semiconductor systems (2DSSs), in achieving population inversion between the second and third electronic subbands. The design allows much greater flexibility in the choice of pumping sources and simplifies considerably the device fabrication. The electronic subband structure of the proposed FIR intersubband laser device has been obtained from a self-consistent calculation via solving coupled Schrodinger and Poisson equations.","PeriodicalId":300064,"journal":{"name":"1998 Conference on Optoelectronic and Microelectronic Materials and Devices. Proceedings (Cat. No.98EX140)","volume":"91 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1998-12-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126466560","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}
Pub Date : 1998-12-14DOI: 10.1109/COMMAD.1998.791578
M. Green, Jianhua Zhao, Aihua Wang
The present paper reports two recent independently confirmed results for silicon solar cell efficiency. An improved efficiency for an individual silicon cell of 24.5% is reported, the highest ever, as is 19.8% efficiency for a multicrystalline silicon cell, the latter representing a 6.5% relative improvement over the previously best result. Not only does the latter result for this relatively low quality material closely approach the 20% efficiency mark, once thought to be a limit on silicon cell performance regardless of multicrystalline material quality, but it also shows the potential for such multicrystalline material exceeding the performance capacity of standard crystalline Czochralski material.
{"title":"Recent progress in silicon solar cells","authors":"M. Green, Jianhua Zhao, Aihua Wang","doi":"10.1109/COMMAD.1998.791578","DOIUrl":"https://doi.org/10.1109/COMMAD.1998.791578","url":null,"abstract":"The present paper reports two recent independently confirmed results for silicon solar cell efficiency. An improved efficiency for an individual silicon cell of 24.5% is reported, the highest ever, as is 19.8% efficiency for a multicrystalline silicon cell, the latter representing a 6.5% relative improvement over the previously best result. Not only does the latter result for this relatively low quality material closely approach the 20% efficiency mark, once thought to be a limit on silicon cell performance regardless of multicrystalline material quality, but it also shows the potential for such multicrystalline material exceeding the performance capacity of standard crystalline Czochralski material.","PeriodicalId":300064,"journal":{"name":"1998 Conference on Optoelectronic and Microelectronic Materials and Devices. Proceedings (Cat. No.98EX140)","volume":"39 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1998-12-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114944175","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}
Pub Date : 1998-12-14DOI: 10.1109/COMMAD.1998.791672
A. Rakić, A. Djurišić, E. H. Li, M. Majewski
Extension of Adachi's model with a Gaussian-like broadening function instead of a Lorentzian one is used to model the optical dielectric function of the alloy Al/sub x/Ga/sub 1-x/As. Gaussian-like broadening is accomplished by replacing the damping constant in the Lorentzian line shape with a frequency dependent expression. In such a manner, the comparative simplicity of analytic formulae of the model is preserved, while the accuracy becomes comparable to more intricate models, and/or models with a significantly greater number of parameters. The employed model describes accurately the optical dielectric function in the spectral range from 1.5 to 6.0 eV in the entire alloy composition range. Relative rms error obtained for the refractive index is below 2.2% for all compositions.
{"title":"Modeling the optical constants of Al/sub x/Ga/sub 1-x/As alloys","authors":"A. Rakić, A. Djurišić, E. H. Li, M. Majewski","doi":"10.1109/COMMAD.1998.791672","DOIUrl":"https://doi.org/10.1109/COMMAD.1998.791672","url":null,"abstract":"Extension of Adachi's model with a Gaussian-like broadening function instead of a Lorentzian one is used to model the optical dielectric function of the alloy Al/sub x/Ga/sub 1-x/As. Gaussian-like broadening is accomplished by replacing the damping constant in the Lorentzian line shape with a frequency dependent expression. In such a manner, the comparative simplicity of analytic formulae of the model is preserved, while the accuracy becomes comparable to more intricate models, and/or models with a significantly greater number of parameters. The employed model describes accurately the optical dielectric function in the spectral range from 1.5 to 6.0 eV in the entire alloy composition range. Relative rms error obtained for the refractive index is below 2.2% for all compositions.","PeriodicalId":300064,"journal":{"name":"1998 Conference on Optoelectronic and Microelectronic Materials and Devices. Proceedings (Cat. No.98EX140)","volume":"55 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1998-12-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130713934","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}
Pub Date : 1998-12-14DOI: 10.1109/COMMAD.1998.791643
J. J. Russell-Harriott, A. Moon, J. Zou, D. Cockayne, B. Usher
Molecular beam epitaxy (MBE) has been widely used to grow epitaxial films, particularly when precise control over the epitaxial layer thickness or abrupt junctions are required. However, oval defects have been found in MBE-grown lattice-mismatched InGaAs/GaAs heterostructures. These act as a primary source of misfit dislocation generation. As a result, it is essential to understand the nature of these oval defects. In this study, we investigate the nature of oval defects using cathodoluminescence (CL) and wavelength dispersive X-ray spectroscopy (WDS).
{"title":"Investigation of oval defects in InGaAs/GaAs strained-layer heterostructures using cathodoluminescence and wavelength dispersive spectroscopy","authors":"J. J. Russell-Harriott, A. Moon, J. Zou, D. Cockayne, B. Usher","doi":"10.1109/COMMAD.1998.791643","DOIUrl":"https://doi.org/10.1109/COMMAD.1998.791643","url":null,"abstract":"Molecular beam epitaxy (MBE) has been widely used to grow epitaxial films, particularly when precise control over the epitaxial layer thickness or abrupt junctions are required. However, oval defects have been found in MBE-grown lattice-mismatched InGaAs/GaAs heterostructures. These act as a primary source of misfit dislocation generation. As a result, it is essential to understand the nature of these oval defects. In this study, we investigate the nature of oval defects using cathodoluminescence (CL) and wavelength dispersive X-ray spectroscopy (WDS).","PeriodicalId":300064,"journal":{"name":"1998 Conference on Optoelectronic and Microelectronic Materials and Devices. Proceedings (Cat. No.98EX140)","volume":"29 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1998-12-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134067500","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}
Pub Date : 1998-12-14DOI: 10.1109/COMMAD.1998.791635
J. Antoszewski, M. Gracey, J. Dell, L. Faraone, G. Parish, Y. Wu, Utkarsh Mishra
In order to characterise the transport properties of the 2DEG in AlGaN/GaN modulation doped field effect transistors, channel magnetoresistance has been measured in the magnetic field range 0-12 T, the temperature range 25-300 K and gate bias range +0.5 V to -2.0 V. Assuming that the 2DEG provides the dominant contribution to the total conductivity, a one carrier fitting procedure has been applied to extract electron mobility and carrier density at each particular value of temperature and gate bias. Consequently, the mobility versus 2DEG density has been obtained for each different temperature. The qualitative analysis of these profiles and comparison with theoretical predictions published by others suggests that for 2DEG densities below 7/spl times/10/sup 12/ cm/sup -2/ the electron mobility is limited by impurity scattering, whereas for densities above this level and up to 1/spl times/10/sup 13/ cm/sup -2/ the electron mobility is controlled by AlGaN/GaN interface roughness.
{"title":"Magneto-transport studies in AlGaN/GaN MODFETs","authors":"J. Antoszewski, M. Gracey, J. Dell, L. Faraone, G. Parish, Y. Wu, Utkarsh Mishra","doi":"10.1109/COMMAD.1998.791635","DOIUrl":"https://doi.org/10.1109/COMMAD.1998.791635","url":null,"abstract":"In order to characterise the transport properties of the 2DEG in AlGaN/GaN modulation doped field effect transistors, channel magnetoresistance has been measured in the magnetic field range 0-12 T, the temperature range 25-300 K and gate bias range +0.5 V to -2.0 V. Assuming that the 2DEG provides the dominant contribution to the total conductivity, a one carrier fitting procedure has been applied to extract electron mobility and carrier density at each particular value of temperature and gate bias. Consequently, the mobility versus 2DEG density has been obtained for each different temperature. The qualitative analysis of these profiles and comparison with theoretical predictions published by others suggests that for 2DEG densities below 7/spl times/10/sup 12/ cm/sup -2/ the electron mobility is limited by impurity scattering, whereas for densities above this level and up to 1/spl times/10/sup 13/ cm/sup -2/ the electron mobility is controlled by AlGaN/GaN interface roughness.","PeriodicalId":300064,"journal":{"name":"1998 Conference on Optoelectronic and Microelectronic Materials and Devices. Proceedings (Cat. No.98EX140)","volume":"152 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1998-12-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114858699","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}
Pub Date : 1998-12-14DOI: 10.1109/COMMAD.1998.791616
H. Tan, L. Fu, M. Johnston, L. Dao, M. Gal, C. Jagadish
Ion (proton) implantation was used to induce intermixing in GaAs/AlGaAs quantum wells. Very large energy shifts (up to 160 meV) were observed after annealing. However, the energy shift was further improved with a repeated implant-anneal sequence. Up to about a factor of two increase in the energy shifts were obtained. This sequence was then used to fabricate laser diodes for multi-wavelength device integration. A remarkable improvement in the laser threshold characteristics was obtained with this sequence compared to a single implant.
{"title":"Improved intermixing in GaAs/AlGaAs quantum well structures through repeated implant-anneal sequence","authors":"H. Tan, L. Fu, M. Johnston, L. Dao, M. Gal, C. Jagadish","doi":"10.1109/COMMAD.1998.791616","DOIUrl":"https://doi.org/10.1109/COMMAD.1998.791616","url":null,"abstract":"Ion (proton) implantation was used to induce intermixing in GaAs/AlGaAs quantum wells. Very large energy shifts (up to 160 meV) were observed after annealing. However, the energy shift was further improved with a repeated implant-anneal sequence. Up to about a factor of two increase in the energy shifts were obtained. This sequence was then used to fabricate laser diodes for multi-wavelength device integration. A remarkable improvement in the laser threshold characteristics was obtained with this sequence compared to a single implant.","PeriodicalId":300064,"journal":{"name":"1998 Conference on Optoelectronic and Microelectronic Materials and Devices. Proceedings (Cat. No.98EX140)","volume":"13 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1998-12-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114955093","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}
Pub Date : 1998-12-14DOI: 10.1109/COMMAD.1998.791663
P. Deenapanray, H. Tan, J. Lengyel, A. Durandet, M. Gal, C. Jagadish
Impurity-free vacancy interdiffusion of GaAs/Al/sub 0.54/Ga/sub 0.46/As quantum wells (QWs) was achieved using SiO/sub x/ capping followed by rapid thermal annealing at 950/spl deg/C. The SiO/sub x/ films were plasma deposited using N/sub 2/O/SiH/sub 4/ flow at 300/spl deg/C and 20 W rf power. The stoichiometry of capping layers were altered by varying the flowrate of N/sub 2/O. In the samples studied, the above process allows continuously variable energy shifts as high as /spl sim/15O meV while still maintaining clearly resolved excitonic behavior. The degree of intermixing is not controlled by x only but, also, by the density of the SiO/sub x/ layers, Our results, therefore, suggest that, in addition to the solid solubility of Ga in SiO/sub x/, intermixing in SiO/sub x/ capped MQW heterostructures depends on the mobility of Ga atoms in the oxide caps.
{"title":"Impurity-free interdiffusion in GaAs/Al/sub 0.54/Ga/sub 0.46/As multiple quantum wells capped with PECVD SiO/sub x/: effect of nitrous oxide flow","authors":"P. Deenapanray, H. Tan, J. Lengyel, A. Durandet, M. Gal, C. Jagadish","doi":"10.1109/COMMAD.1998.791663","DOIUrl":"https://doi.org/10.1109/COMMAD.1998.791663","url":null,"abstract":"Impurity-free vacancy interdiffusion of GaAs/Al/sub 0.54/Ga/sub 0.46/As quantum wells (QWs) was achieved using SiO/sub x/ capping followed by rapid thermal annealing at 950/spl deg/C. The SiO/sub x/ films were plasma deposited using N/sub 2/O/SiH/sub 4/ flow at 300/spl deg/C and 20 W rf power. The stoichiometry of capping layers were altered by varying the flowrate of N/sub 2/O. In the samples studied, the above process allows continuously variable energy shifts as high as /spl sim/15O meV while still maintaining clearly resolved excitonic behavior. The degree of intermixing is not controlled by x only but, also, by the density of the SiO/sub x/ layers, Our results, therefore, suggest that, in addition to the solid solubility of Ga in SiO/sub x/, intermixing in SiO/sub x/ capped MQW heterostructures depends on the mobility of Ga atoms in the oxide caps.","PeriodicalId":300064,"journal":{"name":"1998 Conference on Optoelectronic and Microelectronic Materials and Devices. Proceedings (Cat. No.98EX140)","volume":"22 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1998-12-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116324510","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}
Pub Date : 1998-12-14DOI: 10.1109/COMMAD.1998.791590
D. Pulfrey, A.R. St. Denis, M. Vaidyanathan
Recent progress in the development of compact models for high-speed bipolar transistors with quasi-ballistic base widths (on the order of a mean-free path length) is summarized. The correctness of basing such models on the drift-diffusion equation is examined by comparing results with solutions to the Boltzmann transport equation. Useful and well-founded compact expressions are presented for important dc and ac device parameters.
{"title":"Compact modeling of high-frequency, small-dimension bipolar transistors","authors":"D. Pulfrey, A.R. St. Denis, M. Vaidyanathan","doi":"10.1109/COMMAD.1998.791590","DOIUrl":"https://doi.org/10.1109/COMMAD.1998.791590","url":null,"abstract":"Recent progress in the development of compact models for high-speed bipolar transistors with quasi-ballistic base widths (on the order of a mean-free path length) is summarized. The correctness of basing such models on the drift-diffusion equation is examined by comparing results with solutions to the Boltzmann transport equation. Useful and well-founded compact expressions are presented for important dc and ac device parameters.","PeriodicalId":300064,"journal":{"name":"1998 Conference on Optoelectronic and Microelectronic Materials and Devices. Proceedings (Cat. No.98EX140)","volume":"6 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1998-12-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114428787","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}
Pub Date : 1998-12-14DOI: 10.1109/COMMAD.1998.791678
S. Sakata, P. Vaccaro, S. Yamaoka, I. Umezu, A. Sugimura
We successfully applied the atomic force microscope nano-oxidation process to vanadium thin films for the first time. The oxidized lines were narrower and higher than those of titanium thin films processed under the same conditions, These results show that vanadium is an interesting alternative material for the fabrication of metal/insulator-based nanodevices.
{"title":"Selective oxidation of vanadium thin film surfaces using an atomic force microscope","authors":"S. Sakata, P. Vaccaro, S. Yamaoka, I. Umezu, A. Sugimura","doi":"10.1109/COMMAD.1998.791678","DOIUrl":"https://doi.org/10.1109/COMMAD.1998.791678","url":null,"abstract":"We successfully applied the atomic force microscope nano-oxidation process to vanadium thin films for the first time. The oxidized lines were narrower and higher than those of titanium thin films processed under the same conditions, These results show that vanadium is an interesting alternative material for the fabrication of metal/insulator-based nanodevices.","PeriodicalId":300064,"journal":{"name":"1998 Conference on Optoelectronic and Microelectronic Materials and Devices. Proceedings (Cat. No.98EX140)","volume":"40 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1998-12-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116643774","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}
京公网安备 11010802042870号
京ICP备2023020795号-1
扫码关注我们
求助内容：
应助结果提醒方式：