Pub Date : 2020-06-01DOI: 10.1109/DRC50226.2020.9135147
R. S. Khan, A. H. Talukder, F. Dirisaglik, A. Gokirmak, H. Silva
Phase change memory (PCM) is a high speed, high endurance, high density non-volatile memory technology that utilizes chalcogenide materials such as Ge 2 Sb 2 Te 5 (GST) that can be electrically cycled between highly resistive amorphous and low resistance crystalline phases. The resistance of the amorphous phase of PCM cells increase (drift) in time following a power law [1] , which increases the memory window in time but limits in the implementation of multi-bit-per-cell PCM. There has been a number of theories explaining the origin of drift [1] – [4] , mostly attributing it to structural relaxation, a thermally activated rearrangement of atoms in the amorphous structure [2] . Most of the studies on resistance drift are based on experiments at or above room temperature, where multiple processes may be occurring simultaneously. In this work, we melt-quenched amorphized GST line cells with widths ~120-140 nm, lengths ~390-500 nm, and thickness ~50nm ( Fig. 1 ) and monitored the current-voltage (I-V) characteristics using a parameter analyzer ( Fig. 2 ) in 85 K to 350 K range. We extracted the drift co-efficient from the slope of the resistance vs. time plots (using low-voltage measurements) and observed resistance drift in the 125 K -300 K temperature range ( Fig. 3 ). We found an approximately linear increase in drift coefficient as a function of temperature from ~ 0.07 at 125 K to ~ 0.11 at 200 K and approximately constant drift coefficients in the 200 K to 300 K range ( Fig. 3 inset). These results suggest that structural relaxations alone cannot account for resistance drift, additional mechanisms are contributing to this phenomenon [5] , [6] .
{"title":"Stopping Resistance Drift in Phase Change Memory Cells","authors":"R. S. Khan, A. H. Talukder, F. Dirisaglik, A. Gokirmak, H. Silva","doi":"10.1109/DRC50226.2020.9135147","DOIUrl":"https://doi.org/10.1109/DRC50226.2020.9135147","url":null,"abstract":"Phase change memory (PCM) is a high speed, high endurance, high density non-volatile memory technology that utilizes chalcogenide materials such as Ge 2 Sb 2 Te 5 (GST) that can be electrically cycled between highly resistive amorphous and low resistance crystalline phases. The resistance of the amorphous phase of PCM cells increase (drift) in time following a power law [1] , which increases the memory window in time but limits in the implementation of multi-bit-per-cell PCM. There has been a number of theories explaining the origin of drift [1] – [4] , mostly attributing it to structural relaxation, a thermally activated rearrangement of atoms in the amorphous structure [2] . Most of the studies on resistance drift are based on experiments at or above room temperature, where multiple processes may be occurring simultaneously. In this work, we melt-quenched amorphized GST line cells with widths ~120-140 nm, lengths ~390-500 nm, and thickness ~50nm ( Fig. 1 ) and monitored the current-voltage (I-V) characteristics using a parameter analyzer ( Fig. 2 ) in 85 K to 350 K range. We extracted the drift co-efficient from the slope of the resistance vs. time plots (using low-voltage measurements) and observed resistance drift in the 125 K -300 K temperature range ( Fig. 3 ). We found an approximately linear increase in drift coefficient as a function of temperature from ~ 0.07 at 125 K to ~ 0.11 at 200 K and approximately constant drift coefficients in the 200 K to 300 K range ( Fig. 3 inset). These results suggest that structural relaxations alone cannot account for resistance drift, additional mechanisms are contributing to this phenomenon [5] , [6] .","PeriodicalId":397182,"journal":{"name":"2020 Device Research Conference (DRC)","volume":"38 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2020-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114920884","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 : 2020-06-01DOI: 10.1109/DRC50226.2020.9135156
Seunghyun Lee, S. Kodati, D. Fink, T. Ronningen, A. Jones, J. Campbell, M. Winslow, C. Grein, S. Krishna
Avalanche photodiodes (APDs) are used in short- and mid-wave infrared applications such as optical communication, LIDAR and 3D imaging [1] due to their internal gain, which improves the signal to noise ratio (SNR). However, the multiplication gain ( M ) gives rise to excess noise, caused by the stochastic nature of impact ionization, which can significantly degrade the SNR of APDs. The excess noise is quantitatively measured by excess noise factor, F(M) that is expressed by McIntyre’s local field theory [1] , F(M) = kM + (1-k)[2-(1/M)] where k is the ratio of the impact ionization coefficients for electrons and holes. According to the equation above, the low excess noise factor in APDs can be attained by a low k value.
雪崩光电二极管(apd)由于其内部增益提高了信噪比(SNR)，被用于光通信、激光雷达和3D成像等短波和中波红外应用[1]。然而，由于碰撞电离的随机性，倍增增益(M)会产生过量的噪声，从而显著降低apd的信噪比。过量噪声通过过量噪声因子F(M)定量测量，过量噪声因子F(M)由McIntyre局部场论[1]表示，F(M) = kM + (1-k)[2-(1/M)]，其中k为电子与空穴碰撞电离系数之比。由上式可知，低k值可以使apd的多余噪声系数低。
{"title":"Multiplication characteristics of Al0.4Ga0.07In0.53As avalanche photodiodes grown as digital alloys on InP substrates","authors":"Seunghyun Lee, S. Kodati, D. Fink, T. Ronningen, A. Jones, J. Campbell, M. Winslow, C. Grein, S. Krishna","doi":"10.1109/DRC50226.2020.9135156","DOIUrl":"https://doi.org/10.1109/DRC50226.2020.9135156","url":null,"abstract":"Avalanche photodiodes (APDs) are used in short- and mid-wave infrared applications such as optical communication, LIDAR and 3D imaging [1] due to their internal gain, which improves the signal to noise ratio (SNR). However, the multiplication gain ( M ) gives rise to excess noise, caused by the stochastic nature of impact ionization, which can significantly degrade the SNR of APDs. The excess noise is quantitatively measured by excess noise factor, F(M) that is expressed by McIntyre’s local field theory [1] , F(M) = kM + (1-k)[2-(1/M)] where k is the ratio of the impact ionization coefficients for electrons and holes. According to the equation above, the low excess noise factor in APDs can be attained by a low k value.","PeriodicalId":397182,"journal":{"name":"2020 Device Research Conference (DRC)","volume":"176 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2020-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125812414","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 : 2020-06-01DOI: 10.1109/DRC50226.2020.9135183
Ahmad Zubair, J. Niroula, N. Chowdhury, Yuhao Zhang, J. Lemettinen, T. Palacios
By 2030, about 80% of all US electricity is expected to flow through power electronics. This will require power electronic devices and circuits with much higher efficiency and smaller form-factor than today’s silicon-based systems. III-Nitride semiconductors and other ultra-wide bandgap materials are ideal platforms for the new generation of power electronics thanks to the combination of excellent transport properties and the high critical electric field enabled by their wide bandgap [1] . This talk will discuss recent progress in our group in developing high voltage power transistors and diodes based on wide bandgap materials.
{"title":"Materials and Technology Issues for the Next Generation of Power Electronic Devices","authors":"Ahmad Zubair, J. Niroula, N. Chowdhury, Yuhao Zhang, J. Lemettinen, T. Palacios","doi":"10.1109/DRC50226.2020.9135183","DOIUrl":"https://doi.org/10.1109/DRC50226.2020.9135183","url":null,"abstract":"By 2030, about 80% of all US electricity is expected to flow through power electronics. This will require power electronic devices and circuits with much higher efficiency and smaller form-factor than today’s silicon-based systems. III-Nitride semiconductors and other ultra-wide bandgap materials are ideal platforms for the new generation of power electronics thanks to the combination of excellent transport properties and the high critical electric field enabled by their wide bandgap [1] . This talk will discuss recent progress in our group in developing high voltage power transistors and diodes based on wide bandgap materials.","PeriodicalId":397182,"journal":{"name":"2020 Device Research Conference (DRC)","volume":"515 ","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2020-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"120886967","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 : 2020-06-01DOI: 10.1109/DRC50226.2020.9135172
Niharika Thakuria, A. Saha, S. Thirumala, Daniel S. Schulman, Saptarshi Das, S. Gupta
Among several non-volatile memories (NVMs), ferroelectric (FE) based memories show distinct advantages due to electric field ( E )-driven low-power write [1] - [2] . However, there are other concerns in FE based NVMs (such destructive read in FERAMs [3] , gate leakage in FEFETs with floating inter-layer metal (ILM) [5] and traps and depolarization fields in FEFETs without ILM [4] ). To overcome such issues while retaining the useful features of FE, we propose a Polarization-induced Strain coupled TMD FET (PS FET) [ Fig. 1(a) ] that features (a) polarization-based non-volatile bit-storage (b) E-driven write and (c) coupling of piezoelectricity with dynamic bandgap (EG) tuning of 2D Transition Metal Dichalcogenides (TMDs) for read [ Fig. 1(b) ].
在几种非易失性存储器(nvm)中，基于铁电(FE)的存储器由于电场(E)驱动的低功耗写入[1]-[2]而显示出明显的优势。然而，在基于FE的nvm中存在其他问题(例如FERAMs中的破坏性读取[3]，具有浮动层间金属(ILM)[5]的ffet中的栅极泄漏以及没有ILM[4]的ffet中的陷阱和退极化场)。为了克服这些问题，同时保留FE的有用特性，我们提出了一种极化诱导应变耦合TMD FET (PS FET)[图1(a)]，其特点是(a)基于极化的非易失性位存储(b) e驱动写入和(c)压电耦合与二维过渡金属二硫族化合物(TMDs)的动态带隙(EG)调谐[图1(b)]。
{"title":"Polarization-induced Strain-coupled TMD FETs (PS FETs) for Non-Volatile Memory Applications","authors":"Niharika Thakuria, A. Saha, S. Thirumala, Daniel S. Schulman, Saptarshi Das, S. Gupta","doi":"10.1109/DRC50226.2020.9135172","DOIUrl":"https://doi.org/10.1109/DRC50226.2020.9135172","url":null,"abstract":"Among several non-volatile memories (NVMs), ferroelectric (FE) based memories show distinct advantages due to electric field ( E )-driven low-power write [1] - [2] . However, there are other concerns in FE based NVMs (such destructive read in FERAMs [3] , gate leakage in FEFETs with floating inter-layer metal (ILM) [5] and traps and depolarization fields in FEFETs without ILM [4] ). To overcome such issues while retaining the useful features of FE, we propose a Polarization-induced Strain coupled TMD FET (PS FET) [ Fig. 1(a) ] that features (a) polarization-based non-volatile bit-storage (b) E-driven write and (c) coupling of piezoelectricity with dynamic bandgap (EG) tuning of 2D Transition Metal Dichalcogenides (TMDs) for read [ Fig. 1(b) ].","PeriodicalId":397182,"journal":{"name":"2020 Device Research Conference (DRC)","volume":"31 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2020-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"117253418","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 : 2020-06-01DOI: 10.1109/DRC50226.2020.9135144
A. Jones, S. March, S. Bank, J. Campbell
The 2-μm optical window has recently become an area of great interest for imaging and LIDAR applications due to improved ranging capability and eye safety compared to common telecommunications wavelengths. Avalanche photodiodes (APDs) operating in this spectrum are highly desirable, as their intrinsic gain offers increased sensitivity over traditional photodiodes, further improving receiver sensitivity. HgCdTe, InAs, and InSb, as well as various superlattice materials have been used for this purpose, however, the combination of high electric field and narrow-bandgap absorber yields high dark current. As a result, these APDs are operated at cryogenic temperatures to suppress recombination mechanisms. At the high electric fields required for impact ionization, narrow bandgap materials are also susceptible to band-to-band tunneling, which cannot be suppressed by cooling. The separate absorption, charge, and multiplication (SACM) APD was designed to address this challenge by reducing the electric field in the absorber while maintaining sufficiently high enough field in the multiplication region for impact ionization [1] . This design spatially separates the absorption and multiplication layers, controlling the electric field in the absorber and multiplication layers through an intermediate charge layer. SACM APDs have been widely deployed in the InGaAs/InP and InGaAs/InAlAs materials systems for use in near-infrared telecommunications applications.
{"title":"2-μm-Compatible AlInAsSb Avalanche Photodiodes","authors":"A. Jones, S. March, S. Bank, J. Campbell","doi":"10.1109/DRC50226.2020.9135144","DOIUrl":"https://doi.org/10.1109/DRC50226.2020.9135144","url":null,"abstract":"The 2-μm optical window has recently become an area of great interest for imaging and LIDAR applications due to improved ranging capability and eye safety compared to common telecommunications wavelengths. Avalanche photodiodes (APDs) operating in this spectrum are highly desirable, as their intrinsic gain offers increased sensitivity over traditional photodiodes, further improving receiver sensitivity. HgCdTe, InAs, and InSb, as well as various superlattice materials have been used for this purpose, however, the combination of high electric field and narrow-bandgap absorber yields high dark current. As a result, these APDs are operated at cryogenic temperatures to suppress recombination mechanisms. At the high electric fields required for impact ionization, narrow bandgap materials are also susceptible to band-to-band tunneling, which cannot be suppressed by cooling. The separate absorption, charge, and multiplication (SACM) APD was designed to address this challenge by reducing the electric field in the absorber while maintaining sufficiently high enough field in the multiplication region for impact ionization [1] . This design spatially separates the absorption and multiplication layers, controlling the electric field in the absorber and multiplication layers through an intermediate charge layer. SACM APDs have been widely deployed in the InGaAs/InP and InGaAs/InAlAs materials systems for use in near-infrared telecommunications applications.","PeriodicalId":397182,"journal":{"name":"2020 Device Research Conference (DRC)","volume":"68 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2020-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121000519","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 : 2020-06-01DOI: 10.1109/DRC50226.2020.9135169
P. Shrestha, M. Guidry, B. Romanczyk, Rohit R. Karnaty, N. Hatui, C. Wurm, A. Krishna, S. Pasayat, S. Keller, J. Buckwalter, U. Mishra
N-polar GaN MISHEMTs have recently demonstrated excellent power performance and power-added efficiency at 94 GHz [1] . At mm-wave frequencies and high data rates, the linearity of an RF transistor is an important requisite. Third-order non-linearities lead to undesirable effects such as in-band signal distortion and are therefore important to control. This study presents a novel device concept to enhance the linearity of N-polar GaN MISHEMTs at millimeter wave frequencies (30 GHz and beyond) for low-power receiver application. We have recently reported linearity data on N-polar GaN MISHEMTs with OIP3/P DC of 11.4 dB [2] and 15 dB [3] at 30 GHz. We have observed in [2] , [3] that the peak linearity performance is limited to a narrow input-bias range, resulting in susceptibility to process and temperature variations. Therefore, we explore a novel device structure that can provide its best OIP3/P DC performance over a wide input-bias range.
{"title":"A Novel Concept using Derivative Superposition at the Device-Level to Reduce Linearity Sensitivity to Bias in N-polar GaN MISHEMT","authors":"P. Shrestha, M. Guidry, B. Romanczyk, Rohit R. Karnaty, N. Hatui, C. Wurm, A. Krishna, S. Pasayat, S. Keller, J. Buckwalter, U. Mishra","doi":"10.1109/DRC50226.2020.9135169","DOIUrl":"https://doi.org/10.1109/DRC50226.2020.9135169","url":null,"abstract":"N-polar GaN MISHEMTs have recently demonstrated excellent power performance and power-added efficiency at 94 GHz [1] . At mm-wave frequencies and high data rates, the linearity of an RF transistor is an important requisite. Third-order non-linearities lead to undesirable effects such as in-band signal distortion and are therefore important to control. This study presents a novel device concept to enhance the linearity of N-polar GaN MISHEMTs at millimeter wave frequencies (30 GHz and beyond) for low-power receiver application. We have recently reported linearity data on N-polar GaN MISHEMTs with OIP3/P DC of 11.4 dB [2] and 15 dB [3] at 30 GHz. We have observed in [2] , [3] that the peak linearity performance is limited to a narrow input-bias range, resulting in susceptibility to process and temperature variations. Therefore, we explore a novel device structure that can provide its best OIP3/P DC performance over a wide input-bias range.","PeriodicalId":397182,"journal":{"name":"2020 Device Research Conference (DRC)","volume":"39 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2020-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121115791","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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