近距离热成像系统的光谱匹配因数──微分光谱匹配因数

导出了适用于近距离面目标热成像系统的微分光谱匹配因数（亦称质量因数）且。当Ｔ≈３００Ｋ、λ＝８～１４μｍ时，当Ｔ≈１０００Ｋ，λ＝３～５μｍ时，决定热成像系统的温度分辨率：ＮＥＴＤ，ＭＲＴＤ，ＭＤＴＤ。     

低温NMOSFET的解析模型

利用缓变沟道近似（ＧＣＡ）及准二维分析，提出了在７７～２９５Ｋ温区工作的ＮＭＯＳＦＥＴ的解析模型。建模中不仅考虑迁移率蜕变（电场引起）、载流子速度饱和及沟道调制效应，而且计入温度相关参数的温度特性。模拟结果显示了该模型的正确性及其在低温热载流子效应中的应用潜力。     

在含有InSb非晶过渡层的GaAs衬底上用分子束外延生长InSb薄膜

在（１００）取向半绝缘ＧａＡｓ衬底上，采用独特的含有ＩｎＳｂ非晶过渡层的两步分子束外延（ＭＢＥ）生长了异质外延ＩｎＳｂ薄膜。ＩｎＳｂ外延层表面为平滑镜面，外延层厚度约为６μｍ，导电类型为ｎ型，室温（３００Ｋ）和液氮（７７Ｋ）霍尔载流子浓度分别为ｎ＿（３００Ｋ）：２．０×１０￣（１６）ｃｍ￣（－３）和ｎ＿（７７Ｋ）：２．４×１０￣（１５）ｃｍ￣（－３）；电子迁移率分别为μ＿（３００Ｋ）：４１０００ｃｍ￣２Ｖ￣（－１）Ｓ＿（－１）和μ＿（７７Ｋ）：５１２００ｃｍ￣２Ｖ￣（－１）Ｓ￣（－１）。ＩｎＳｂ外延层双晶衍射半峰宽为１９８ａｒｃｓ，最好的ＩｎＳｂ外延层的半峰宽小于１５０ａｒｃｓ。采用ＩｎＳｂ非晶过渡层有效地降低了外延层中的位错密度，改善了ＩｎＳｂ外延层的质量。     

LPE法在Si衬底上生长SiGe层的方法及电子特性的研究

本文介绍了在电阻率为（７７～３００）ｋΩ·ｃｍ的ｎ型（１１１）Ｓｉ衬底上用ＬＰＥ法生长高质量Ｓｉ１－ＸＧｅｘ单晶薄层（其厚度一般为１～３μｍ）的生长条件，并对引入的缺陷进行了ＴＥＭ研究，结果表明其缺陷密度和用ＭＢＥ及超高真空ＣＶＤ法生长的同样厚度和组分的Ｓｉ１－ｘＧｅｘ薄层的缺陷密度相等甚至更低．霍尔迁移率μＨ与温度有μＨ∝Ｔｍ的关系，（在Ｔ＝８０～３００Ｋ时，ｍ＝－０．９５）．当ｘ＞０．８５时，μＨ的测量值和由Ｋｒｉｓｈｎａｍｕｒｔｈｙ计算的理论值相符，ｘ＜０．８５，测量值仅为理论值的７０％．由Ｂｉ杂质     

适用于宽温度范围和不同沟遭掺杂浓度的MOSFET反型层载流子迁移率模型

本文基干决定载流子迁移率的晶格散射、电离杂质散射、表面粗糙散射等三种主要散射机制的考虑，提出了一个有较明确物理意义的精度和实用性兼顾的ＭＯＳＦＥＴ反型层中载流子迁移率半经验模型．模型适用的温度范围为５Ｋ～３７０Ｋ，沟道掺杂浓度范围为１e14ｃｍ－３－１e１８ｃｍ－３．模型的计算结果同实验数据符合很好．     

工作在液氮温度下的低频低噪声双极晶体管的研究

对双极晶体管的低温物理模型和低频噪声模型进行了研究，认为低温下硅双极晶体管电流增益下降的主要原因是低温下非理想基极电流的增加。同时指出，低温下硅双极晶体管１／ｆ噪声的增大，是由于低温下电流增益的减小和载流子在体内和表面的复合增加。通过优化设计，做出了一种低温、低频、低噪声硅双极晶体管。测试表明，在室温（３００Ｋ）下，电流增益、低频转折频率、１ｋＨｚ点的噪声电压分别为β≥８００，ｆ＿Ｌ≤３０Ｈｚ，Ｅｎ（１ｋＨｚ）≤１．５ｎＶ／　　；低温（７７Ｋ）下，电流增益、低频转折频率、１ｋＨｚ点的噪声电压分别为β≥３０，ｆ＿Ｌ≤３００Ｈｚ，Ｅｎ（１ｋＨｚ）≤１．２ｎＶ／。     

SOI材料MOS器件高温特性的模拟

本文介绍了ＳＯＩ材料ＭＯＳ器件内部特性（杂质浓度分布、载流子浓度分布、电流密度分布及电势分布）在３００Ｋ和５３７Ｋ条件下的模拟结果，并进行了理论分析和验证。     

Siδ掺杂GaAs多量子阱的磁量子输运

使用ＭＢＥ技术低温生长了含有３个Ｓｉδ掺杂层的ＧａＡｓ外延片，形成三量子阱结构。在４．２～３００Ｋ温区０．１Ｔ的电磁铁上测量了样品载流子浓度和迁移率随温度的变化。在０．３～４．２Ｋ（＾３Ｈｅ温区）和０～７Ｔ强磁场下测量了样品的横向磁阻、纵向磁阻和霍尔电阻。观察到了横向磁阻的ＳｄＨ振荡和纵向磁阻的抗磁ＳｄＨ振荡。根据实验结果着重讨论了纵向磁阻振荡的起源以及霍尔振荡的含义，简单分析了δ掺杂二维电子气中     

低温多晶硅发射极晶体管电流增益和截止频率的解析模型

本文综合考虑了多晶硅发射极的载流子输运障碍,界面氧化物遂穿、晶粒间界杂质分凝和界面能带弯曲等因素,以及禁带变窄效应、低温下载流子冻析效应和浅能能补偿杂质隐阱效应,建立了低温多晶硅发射极晶体管电流增益和截止频率的解析模型,对电流增益和截止频率的温度关系进行了理论分析并与３００Ｋ和７７Ｋ下的实测结果进行了比较。     

工作在液氮温度下的低频低噪声双极晶体管的研究

对双极晶体管的低温物理模型和低频噪声模型进行了研究，认为低温下硅双极晶体管电流增益下降的主要原因是低温下非理想基极电流的增加。同时指出，低温下硅双极晶体管１／ｆ噪声的增大，是由于低温下电流增益的减小和载流子在体内和表面的复合增加。通过优化设计，做出了一种低温、低频、低噪声硅双极晶体管。测试表明，在室温（３００Ｋ）下，电流增益、低频转折频率、１ｋＨｚ点的噪声电压分别为β≥８００，ｆＬ≤３０Ｈｚ，Ｅｎ     

Pb(Mg1/3Nb2/3)O3-0.3PbTiO3单晶紫外可见近红外光学性质

通过温度依赖的透射和反射光谱研究了在准同型相界附近的Pb(Mg_(1/3)Nb_(2/3))O_3-0.3PbTiO_3(PMN-0.3PT)单晶光学性质.这种禁带宽度随温度范围不同变化规律不同现象,揭示了PMN-PT单晶温度依赖的复杂相结构.禁带宽度Eg在303 K是3.25 e V,临界点Ea是3.93 e V,临界点Eb是4.65 e V,它们随着温度的上升而下降,在453 K禁带宽度Eg是3.05 eV,临界点Ea是3.57 eV,临界点Eb是4.56 eV.这三个跃迁能量Eg、Ea、Eb分别对应从O 2p到Ti d、Ni d、Pb 6p轨道跃迁.它们随温度上升而下降的变化规律可以用晶格热膨胀和电子声子相互作用理论来解释.通过Tauc-Lorentz色散模型拟合得到了303 K到453 K温度范围的Pb(Mg_(1/3)Nb_(2/3))O3-0.3PbTiO_3单晶光学常数及其随温度的变化规律,发现折射率n随着温度的升高而升高.     

BILOW-simulation of low-temperature bipolar device behavior

The BILOW simulation program for investigating bipolar transistor behavior in the temperature range 77-300 K is discussed. Differences between the numerical approaches required for simulation of low-temperature behavior compared to room-temperature simulation are presented. Efficient numerical models for the physical parameters in the carrier transport equations and Poisson's equation for the temperature range of 77-300 K, including a new highly accurate numerical model for the temperature and doping concentration dependence of carrier mobility, are discussed. A temperature- and doping-concentration-dependent model for apparent bandgap narrowing is also discussed. The internal characteristics of a typical bipolar transistor are simulated over the 300-77 K range. The behavior of current gain β and the unity gain frequency f_T versus collector current density for different temperatures are calculated and discussed     

MOS device modeling at 77 K

The state of the art in self-consistent numerical low-temperature MOS modeling is reviewed. The physical assumptions that are required to describe carrier transport at low ambient temperatures are discussed. Particular emphasis is placed on the models for space charge (impurity freeze-out), carrier mobility (temperature dependence of scattering mechanisms at a semiconductor-insulator interface), and carrier generation-recombination (impact ionization). The differences with regard to the numerical methods required for the solution of low-temperature models compared to room-temperature models are explained. Typical results obtained with the simulator MINIMOS 4 are presented. These include comparisons of short-channel effects and hot-electron phenomena such as energy relaxation and avalanche breakdown at 77 K and 300 K ambient temperatures     

Carrier multiplication in submicrometre pMOS transistors operated at cryogenic temperatures

The temperature and bias dependence of the carrier multiplication M(I/sub bulk//I/sub drain/) in submicrometre pMOS transistors has been characterised and studied over the temperature range of 30-300 K. In addition, a model which reproduces the bias dependence of M over the measured range of temperature can be extrapolated down to 4.2 K to predict the internal bulk potential and its related 'kink effect'. The agreement between data and the prediction of the model confirms that the gate voltage and temperature dependence of the mean free path plays the key role in determining the carrier multiplication characteristics of submicrometre pMOS transistors, operating in the temperature range of 4.2-300 K.<>     

Luminescence and bandgap studies of high purity MgXZn1−XTe Ternary Alloys

High purity Mg_XZn_1−XTe alloys in the range of 0 < x < 0.45 have been prepared by the Bridgman technique. Wavelength modulated reflectivity measurements have been performed at 300 K. The structure of the spectra near the fundamen-tal edge is similar to the one for ZnTe. The bandgap va-riation versus the composition x is Eg (x) = 2.271 + 0.7 x + 0.6 x². Cathodoluminescence at 300K and 110K shows a single bandedge narrow peak. The variation with composition of the emission peak energy Ep (X) follows the same law as Eg (x). Undoped crystals are highly resistive (> 10⁵Ωcm) but when phosporus is introduced into the melt, the resis-tivity decreases to 10³ Ωcm.     

Free carrier optical absorption at 10.6 μm in GaAs

Optical absorption measurements at 10.6 μm have been perfor-med in chromium doped GaAs samples using a calorimetric tech-nique at 300 K, and an optical system to determine the varia-tion of the absorption versus temperature between 300 K and 650 K. Hall effect measurements have also been carried out in the same temperature range. The optical absorption cross sec-tion for both electrons and holes are discussed and experi-mentally determined. A semi-empirical formula is deduced which permit the calculation of the 10.6 μm free carrier absorption at any temperature and doping level provided the electron mobility is known. Besides free carrier and multi-phonon absorption another mechanism must be considered to explain the experimental data. Possible effect of small pre-cipitates is discussed.     

流体静压力下Hg_(1-x)Cd_xTe p-n结的伏安特性

在77K和室温下,研究了Hg_(1-x)Cd_xTe(x=0.5)p—n结伏安特性随流体静压力的变化,从中得到了禁带宽度E_g的压力系数。结果表明,在低压范围(01.4GPa),E_g～P关系明显偏离线性。实验还观察到,在正、反向小偏压区域,I—V特性随压力的变化呈现“反常”行为。     

MOCVD生长带有MQB的量子阱激光器材料

用ＭＯＣＶＤ生长发射波长为８０８ｎｍ的ＡＬＧａＡｓ／ＧａＡｓ量子阱激光器材料。通过在激光器材料的波导中加入多量子势垒（ＭＱＢ）层，有效地限制电子在阱内的复合以及高能电子溢出阱外，从而降低了激光器的阈值电流，提高了它的特征温度。增加了ＭＱＢ后，器件的阈值电流密度Ｉ＿（ｔｈ）从原来的４００～６００Ａ／ｃｍ￣２下降到３００～４００Ａ／ｃｍ￣２，特征温度从１６０Ｋ提高到２１０Ｋ。     

Experimental characterization and modeling of electron saturationvelocity in MOSFETs inversion layer from 90 to 350 K

From saturation transconductance of devices of 0.25-μm CMOS technology, the saturation velocity of electrons (ν_sat) in the inversion layer from 90 to 350 K has been determined. The extracted ν_sat at 300 K was 7.86×10⁶ cm/s, which is significantly lower than that of bulk silicon (ν_sat-blk) and has a much weaker temperature dependence. The ratio ν_sat-blk /ν_sat is 1.27 at 300 K, and is increased to 1.68 at 90 K. Consistent values of ν_sat have been determined for devices of three vastly different MOS technologies, demonstrating the technology independence of ν_sat. The results are useful for developing and testing theoretical carrier transport models, and are of practical importance in estimating the ultimate speed performance of surface MOSFETs. An empirical model for ν_sat as a function of temperature has also been derived for application in predictive device simulation     

Temperature‐dependent Hall‐effect measurements of p‐type multicrystalline compensated solar grade silicon

In this study, we have investigated the Hall majority carrier mobility of p‐type, compensated multicrystalline solar grade silicon (SoG‐Si) wafers for solar cells in the temperature range 70–373 K. At low temperature (~70 K) the difference in the mobilities measured for the compensated and the uncompensated reference samples is the highest, and the measured mobility shows dependence on the compensation ratio. Mobilities decrease with increasing temperature, and towards room temperature, the mobilities of the different samples are in the same range. The measurements show that, for these samples, the contribution from lattice scattering is dominating over ionized impurity scattering at room temperature. In the range of interest for silicon solar cells (above room temperature), the trend in carrier mobility is similar for all the samples, and the measured value for the sample with low compensation ratio and low doping density is comparable to the uncompensated references. A comparison of resistivity and majority carrier density measured by the Hall setup at room temperature and by four‐point probe and glow discharge mass spectroscopy, respectively, is reported as well. Copyright © 2012 John Wiley & Sons, Ltd.