52nd Annual Device Research Conference最新文献

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4H-silicon carbide mesfet with 2.8 W/mm rf power density 具有2.8 W/mm射频功率密度的4h碳化硅介面
52nd Annual Device Research Conference Pub Date : 1994-06-20 DOI: 10.1109/DRC.1994.1009401
J. Palmour, C. Weitzel, K. Nordquist, C. Carter
{"title":"4H-silicon carbide mesfet with 2.8 W/mm rf power density","authors":"J. Palmour, C. Weitzel, K. Nordquist, C. Carter","doi":"10.1109/DRC.1994.1009401","DOIUrl":"https://doi.org/10.1109/DRC.1994.1009401","url":null,"abstract":"Silicon carbide has tremendous potential for high power microwave devices because of its high breakdown electric field (4x106 V/cm), high thermal conductivity (4.9 W/cm-K), high saturated electron drift velocity ( 2 . 0 ~ 107 cm/sec) and low dielectric constant (10.0). The high velocity allows the devices to operate at relatively high frequencies despite the low mobility of S i c . The high breakdown field allows about ten times higher voltages to be applied for a given channel doping, which should allow a much higher output power density to be achieved than with Si or GaAsl . Submicron MESFETs have been previously fabricated in 6H-Sic and have shown desirable microwave performance with RF output powers of about 1 W/mm at 1-2 G H Z ~ ~ ~ . However, another polytype, 4H-SiC, shows even more potential for high power, high frequency operation, because its electron mobility (>550 cm2/V-sec) is about twice that of 6H-Sic. Thus we report the first DC, S-parameter, and output power results obtained with 4H-Sic MESFETs.","PeriodicalId":244069,"journal":{"name":"52nd Annual Device Research Conference","volume":"79 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1994-06-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131769991","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}
引用次数: 2
Near-ideal breakdown Si/SiGe heterojunction bipolar transistors for microwave power 微波功率用近理想击穿Si/SiGe异质结双极晶体管
52nd Annual Device Research Conference Pub Date : 1994-06-20 DOI: 10.1109/DRC.1994.1009408
K. Hobart, F. Kub, N. Papanicolaou, W. Kruppa, P. Thompson
{"title":"Near-ideal breakdown Si/SiGe heterojunction bipolar transistors for microwave power","authors":"K. Hobart, F. Kub, N. Papanicolaou, W. Kruppa, P. Thompson","doi":"10.1109/DRC.1994.1009408","DOIUrl":"https://doi.org/10.1109/DRC.1994.1009408","url":null,"abstract":"","PeriodicalId":244069,"journal":{"name":"52nd Annual Device Research Conference","volume":"244 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1994-06-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115833963","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}
引用次数: 0
Conductivity modulation lag during IGBT turn on in resonant converter applications 谐振变换器中IGBT导通时电导率调制滞后
52nd Annual Device Research Conference Pub Date : 1994-06-20 DOI: 10.1109/DRC.1994.1009405
I. Widjaja, A. Kurnia, D. Divan, K. Shenai
{"title":"Conductivity modulation lag during IGBT turn on in resonant converter applications","authors":"I. Widjaja, A. Kurnia, D. Divan, K. Shenai","doi":"10.1109/DRC.1994.1009405","DOIUrl":"https://doi.org/10.1109/DRC.1994.1009405","url":null,"abstract":"A novel physical mechanism is identified in the IGBT t u n on waveforms when switched in resonant converter applications. Dynamic saturation of the forward voltage drop Vce has been observed in excess of 1OV followed by voltage spikes under varying di/dt switching conditions. This value of Vce is far in excess of that due to inductance caused by the package and module substrate assembly. The additional di/dt induced voltage results from the inductive effect within the intrinsic device. As the device is being turned on, the rate of conductivity modulation of the drift region lags behind the rate at which the excess carriers are removed. Computer simulations using an advanced 2D mixed-mode circuit simulator suggest significant. amount of drift region \" conductivity modulation lag 'I. In this simulator, 2D device carrier dynamics is calculated in an actual circuit switching environment, and thus, allows for the study of plasma spreading as the circuit boundary conditions are changed. This mechanism results in excessive turn on power loss in fast-switching IGBT's where device speed is increased using carrier lifetime killers. A circuit simulation model is developed that accurately predicts the turn on waveforms.","PeriodicalId":244069,"journal":{"name":"52nd Annual Device Research Conference","volume":"19 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1994-06-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"117189609","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}
引用次数: 8
Polarization insensitivity of a high performance electroaibsorption modulator based on strained GaInAs/AlInAs MQW 基于应变GaInAs/AlInAs MQW的高性能电吸收调制器的极化不灵敏度
52nd Annual Device Research Conference Pub Date : 1994-06-20 DOI: 10.1109/DRC.1994.1009447
S. Chelles, Julie Harmand, M. Allovon, P. Voisin
{"title":"Polarization insensitivity of a high performance electroaibsorption modulator based on strained GaInAs/AlInAs MQW","authors":"S. Chelles, Julie Harmand, M. Allovon, P. Voisin","doi":"10.1109/DRC.1994.1009447","DOIUrl":"https://doi.org/10.1109/DRC.1994.1009447","url":null,"abstract":"Polarization insensitivity is an important challenge for optical-fiber telecommunications. Since the incident light polarization state is random after propagation through optical fibers, it is essential that in-line optical components be polarization independent'. We report on the first polarization insensitive electroabsorption modulator (EA) using strained GaInAdAlInAs multiple quantum wells (MQW). This modulator operates in the 1.55-1.6 pm wavelength range with performances even higher than of any EA MQW modulator.","PeriodicalId":244069,"journal":{"name":"52nd Annual Device Research Conference","volume":"45 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1994-06-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115588547","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}
引用次数: 0
Novel processing approach for sub-micron heterojunction bipolar transistors 亚微米异质结双极晶体管的新型加工方法
52nd Annual Device Research Conference Pub Date : 1994-06-20 DOI: 10.1109/DRC.1994.1009427
C. Dai, W. Liu, A. Massengale, A. Kameyama, J. S. Harris
{"title":"Novel processing approach for sub-micron heterojunction bipolar transistors","authors":"C. Dai, W. Liu, A. Massengale, A. Kameyama, J. S. Harris","doi":"10.1109/DRC.1994.1009427","DOIUrl":"https://doi.org/10.1109/DRC.1994.1009427","url":null,"abstract":"The fabrication of high reliability, high current gain and low l/f noise heterojunction bipolar transistors (HBTs) has utilized a fully depleted thin AlGaAs layer to eliminate base surface recombination current. Higher frequency and lower power devices require scaling to sub-micron dimensions and control of this passivation ledge is a difficult processing problem that has precluded prior investigation of sub-micron devices. In this study, we report the development of a novel self-alignment approach using e-beam lithography to realize passivation ledges as small as 0.1 ym. This new fabrication approach allows us to experimentally investigate the limits of passivation for HBTs and establish that the minimum ledge to eliminate all recombination is 0.3pm. we have also simulated the performance of these HBTs by both analytical models and a 2Dsimulator, Semi-Cad. Our experimental and theoretical results are in excellent agreement and enable one to optimize high speed or low power structures with smaller ledges where complete passivation is not achieved. The maximum current gain in our fully passivated devices is base transport limited at 900.","PeriodicalId":244069,"journal":{"name":"52nd Annual Device Research Conference","volume":"27 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1994-06-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125875927","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}
引用次数: 1
High-performance AlInP/AlImAs/GaInAs HEMT with a partially-doped graded pseudomorphic channel 具有部分掺杂渐变伪晶通道的高性能AlInP/AlImAs/GaInAs HEMT
52nd Annual Device Research Conference Pub Date : 1994-06-20 DOI: 10.1109/DRC.1994.1009454
K. Chough, J. Song, C. Caneau, B.W.-P. Hong
{"title":"High-performance AlInP/AlImAs/GaInAs HEMT with a partially-doped graded pseudomorphic channel","authors":"K. Chough, J. Song, C. Caneau, B.W.-P. Hong","doi":"10.1109/DRC.1994.1009454","DOIUrl":"https://doi.org/10.1109/DRC.1994.1009454","url":null,"abstract":"Despite significant improvements of the transconductance and speed of pseudomorphic AlInAs/GaInAs HEMTs, these devices suffer from low channel breakdown voltage and large outputconductance. Especially, in power applications, the drain current handling capability is limited by low channel and gate breakdown voltages [l]. This is mainly due to lower bandgap of the channel and strong localization of the 2DEG distribution at the interface. Our previous work showed that this problem can be solved by grading indium mole fraction in the pseudomorphic GaInAs channel [2]. In this work, we demonstrate a novel InP-based HEMT where partial grading of doping is employed in lower half of the pseudomorphic channel. This resulted in significant increase of the drain current handling cability without degrading channel breakdown voltage and other dc and rf performances. The device structures were grown by low-pressure OMCVD. All five device structures were identical except that the channel composition was changed in a systematic way. The total channel thickness also remained at 300 A. The Gal,,In,As channel of Devices A and By had a dorm indium composition (x) of 0.53 and 0.7, respectively. Devices C had a channel with x graded from 0.7 to 0.53. Device D was similar to Device C except the doping level in the doped AlInAs layer is reduced and the doping of the channel is graded from 0 ~m-~ to 2 x IOl7 ~m-~. For comparison, the whole channel of Device E was unformly doped (1 x lo1* ~m-~) without AlInAs doped layer above the channel. An &,2h08P ternary is used as a Schottky layer to increase the Schottky barrier height. A standard 0.7 pm gate FET processing was employed to fabricate the devices on the epitaxial wafers. All five devices had excellent Schottky diode characteristics. This is due to a high bandgap (-1.8 ev) of the high-quality &2%.8P Schottky layer. The transconductance (gm) and current-gain cutoff frequency (fT) were signrficantly increased with the increase of the indium composition as expected. Device B had 5 1 % higher gm (800 mS/mm) and 30 % higher fT (61 GHz) than Device A. However, the channel breakdown voltage (BVh=3.5V) and output conductance &=85 mS/mm) of device B became considerably poorer. However, by grading the channel composition (Device C), channel breakdown voltage (BVb=9V) and output conductance (&,do mS/mm) characteristics can be significautly improved. Final challenge is to modi6 the structure of Device C to increase the drain current handling capability, while keeping high gm and fT. As clear With Device D (graded x=0.7 to 0.6, and partially doped), doping grading significantly increases the drain current density (ID max = 1000 mA/m) and decreases go (24 mS/mm) while gm (590 mS/mm), fT (47 GHz), and BVh (7 V) are comparable to those of Device C. Device D also showed very high power-gain cutoff fiequency (f-) of 1 10 GHz. In conclusion, the studies demonstrate that the partiallydoped graded channel of InP-based pseudomorphic HEh4T's ","PeriodicalId":244069,"journal":{"name":"52nd Annual Device Research Conference","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1994-06-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130285111","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}
引用次数: 0
Vertical cavity phase flip modulators and reflection-transmission amplitude modulators for efficient beam steering and optical switching 垂直腔相位翻转调制器和反射传输调制器,用于有效的光束转向和光开关
52nd Annual Device Research Conference Pub Date : 1994-06-20 DOI: 10.1109/DRC.1994.1009446
J. Trezza, J. Harris
{"title":"Vertical cavity phase flip modulators and reflection-transmission amplitude modulators for efficient beam steering and optical switching","authors":"J. Trezza, J. Harris","doi":"10.1109/DRC.1994.1009446","DOIUrl":"https://doi.org/10.1109/DRC.1994.1009446","url":null,"abstract":"","PeriodicalId":244069,"journal":{"name":"52nd Annual Device Research Conference","volume":"9 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1994-06-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132612914","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}
引用次数: 0
High luminous flux semiconductor wafer-bonded (Al/sub x/Ga/sub 1-x/)/sub 0.5/In/sub 0.5/P/GaP large area light-emitting diodes 高光通量半导体晶圆键合(Al/sub x/Ga/sub 1-x/)/sub 0.5/In/sub 0.5/P/GaP大面积发光二极管
52nd Annual Device Research Conference Pub Date : 1994-06-20 DOI: 10.1109/DRC.1994.1009461
F. Kish, D. Defevere, D. A. Vanderwater, G. Trott, R. J. Weissb
{"title":"High luminous flux semiconductor wafer-bonded (Al/sub x/Ga/sub 1-x/)/sub 0.5/In/sub 0.5/P/GaP large area light-emitting diodes","authors":"F. Kish, D. Defevere, D. A. Vanderwater, G. Trott, R. J. Weissb","doi":"10.1109/DRC.1994.1009461","DOIUrl":"https://doi.org/10.1109/DRC.1994.1009461","url":null,"abstract":"Significant improvements have been achieved in the efficiency of visible 9 light-emitting diodes (LEDs) in the green to red portion of the spectrum by employin AIGalnP/GaAs emitters formed by metalorganic chemical vapor deposition (MOCVD). Recently, it has been demonstrated that the extraction efficiency of these devices (grown on absorbing GaAs substrates) can be doubled by semiconductor wafer bonding a transparent GaP substrate in place of the GaAs. The resulting transparent-substrate (TS) AIGalnP/GaP LEDs exhibit luminous efficiencies (>15 ImNV) that exceed that of a typical 60 W tungsten sources in the yellow-green to red (570-640 nm) portion of the spectrum.2 Despite the high efficiency of these sources, LEDs are typically limited to low flux (power) applications as a result of the high thermal resistance (220°CA#) of the LED lamps.","PeriodicalId":244069,"journal":{"name":"52nd Annual Device Research Conference","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1994-06-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130642400","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}
引用次数: 0
Performance of the AlGaAsSb/GaInAs/GaInAs PNP and AlInAs/GaAsSb/AlInAs NPN HBTs
52nd Annual Device Research Conference Pub Date : 1994-06-20 DOI: 10.1109/DRC.1994.1009432
A. Fathimulla, H. Hier, D. Gutierrez
{"title":"Performance of the AlGaAsSb/GaInAs/GaInAs PNP and AlInAs/GaAsSb/AlInAs NPN HBTs","authors":"A. Fathimulla, H. Hier, D. Gutierrez","doi":"10.1109/DRC.1994.1009432","DOIUrl":"https://doi.org/10.1109/DRC.1994.1009432","url":null,"abstract":"Interest is growing in the InP-based HBTs for high-speed complementary digital and push-pull amplifier applications. The majority of the research done on the InP-based HBTs has been concentrated on the InP/GaInAs and AlInAdGaInAs systems. In these devices, the emitter-tobase junction is generally graded to minimize the effect of large conduction band spike We report the growth and performance of AlInAs/GaAsSb/AlInAs npn HBTs and AlGaAsSb/GaInAs/GaInAs pnp HBTs lattice matched to InP substrates. In these structures all of the band-gap difference is in the valence band for AIInAdGaAsSb (0.65 eV) and conduction band for AIGaAsSb/GaInAs (1.1 eV) junctions, resulting in the large AEv (AE,) and small AE, (AE,) desirable for high performance npn (pnp) HBTs. For the first time, we have demonstrated a AlGaAsSb/GaInAs/GaInAs pnp HBT and obtained excellent microwave performance for both npn and pnp HBTs. ' The HBT structures were grown by MBE using fluxes of Sb, and As,. The epitaxial structure for the npn HBT consisted of a 500 nm n'-GaInAs subcollector, a 300 nm n-AlInAs collector, a 60 nm p'-GaAsSb base, a 2 nm InP etch stop, a 100 nm n-AlInAs emitter and followed by n'-GaInAs subcollector. The structure for the pnp HBT consisted of a 400 nm p'-GaInAs subcollector, a 400 nm P-GaInAs collector, a 60 nm n'-GaInAs, 70 nm p-A1 ,Ga,As ,,Sb 44 emitter and a 350 nm p'=-GaInAs subemitter. The GaAsSb hole mobility at a concentration of 2e19 was twice the hole mobility of GaInAs. This higher mobility will lower the base resistance and improve the performance of the GaAsSb base devices over conventional HBTs with GaInAs bases. Details of the processing of self-aligned HBTs were published in reference 1. A collector current density of 6x104 A/cm2 and an h,of 25 were measured for a 5x5 pm size npn device. We measured a BV,,, of about 1OV for the npn HBT. For the pnp HBT, a BV,,,, of 12 V, an h, of 10, and a collector current density of 2x104 A/cm2 were obtained. The high frequency performance of the HBTs in the common emitter configuration was measured with a Cascade on-wafer probe. The extrapolated f, and f,,, were 45 GHz and 34 GHz for a 5x5 pm size double heterojunction npn HBT. An f,,, of 14 GHz for a 4x6 pm pnp HBT was measured. These experimental results indicate that Sb-based npn and pnp HBTs latticematched to InP substrate are an excellent choice for complementary applications. Reference:","PeriodicalId":244069,"journal":{"name":"52nd Annual Device Research Conference","volume":"11 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1994-06-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115039857","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}
引用次数: 0
Quantum cascade laser: a unipolar intersubband semiconductor laser operating at 125 K 量子级联激光器:工作在125 K的单极子带间半导体激光器
52nd Annual Device Research Conference Pub Date : 1994-06-20 DOI: 10.1109/DRC.1994.1009440
F. Capasso, J. Faist, D. Sivco, C. Sirtori, A. L. Hutchinson, S. Chu, A. Cho
{"title":"Quantum cascade laser: a unipolar intersubband semiconductor laser operating at 125 K","authors":"F. Capasso, J. Faist, D. Sivco, C. Sirtori, A. L. Hutchinson, S. Chu, A. Cho","doi":"10.1109/DRC.1994.1009440","DOIUrl":"https://doi.org/10.1109/DRC.1994.1009440","url":null,"abstract":"A new semiconductor injection laser (Quantum Cascade Laser) which differs in a fundamental way fiom diode lasers has been demonstrated. It relies on only one type of carrier (it is a unipolar semiconductor laser), and on electronic transitions between conduction band energy levels of quantum wells. Such intersubband lasers were originally proposed 25 years ago, but despite considerable effort thip ;s the first structure to achieve laser action. The present device operates at a wavelength of 4.26 microns, but since the wavelength is entirely determined by quantum confinement, it can be tailored from the mid-infrared to the submillimeter region using the same heterostructure material. Electrons streaming down a potential staircase sequentially emit photons at the steps. The latter consist of coupled quantum wells in which population inversion between discrete conduction band excited states is achieved in a 4-level atomic like laser scheme using tunneling injection. The AlInAs/GaInAs structure comprises 25 stages, each consisting of a graded gap n-type injection layer and a three coupled-well active region, cladded by waveguiding layers. The undoped active region includes 0.8 nm and 3.5 nm thick GaInAs wells separated by 3.5 nm AlInAs barriers. The reduced spatial overlap between the states of the laser transition and the strong tunnel-coupling to a nearby 2.8 nm GaInAs well ensure population inversion. A dramatic narrowing of the emission spectrum and attendant order of magnitude increase of the optical power above a current threshold = 10 kA/cm2 provide direct evidence of laser action. Powers = 20 mW in pulsed operation have been obtained at 80 K. Operating temperatures up to 125 K have been achieved with 5 mW of power. An outstanding feature of this laser is that the gain is much less sensitive to temperature than conventional semiconductor lasers. A detailed study of the temperature dependence of the threshold indicates a To = 125 K. In addition, the intrinsic linewidth of these lasers is expected to be Schawlow-Townes limited, similar to atomic lasers, without the linewidth enhancement factor typical of diode lasers. For a preliminary account of the operation of this laser at 10 K see Ref. 2.","PeriodicalId":244069,"journal":{"name":"52nd Annual Device Research Conference","volume":"14 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1994-06-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116792361","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}
引用次数: 0
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