硅基HgCdTe光伏器件的暗电流特性分析

对硅基HgCdTe中波器件进行了变温电流电压特性的测试和分析。测量温度从30K到240K，得到R0对数与温度的1000／T的实验曲线及拟合结果。同时选取60K、80K及110K下动态阻抗R与电压V的曲线进行拟合分析。研究表明在我们器件工作的温度点80K，零偏压附近主要的电流机制是产生复合电流和陷阱辅助隧穿电流。要提高器件的水平，必须降低陷阱辅助隧穿电流和产生复合电流对暗电流的贡献。     

硅基HgCdTe光伏器件的暗电流特性分析

对硅基HgCdTe中波器件进行了变温电流电压特性的测试和分析.测量温度从30K到240K,得到R0对数与温度的1000/T的实验曲线及拟合结果.同时选取60K、80K及110K下动态阻抗R与电压V的曲线进行拟合分析.研究表明在我们器件工作的温度点80K,零偏压附近主要的电流机制是产生复合电流和陷阱辅助隧穿电流.要提高器件的水平,必须降低陷阱辅助隧穿电流和产生复合电流对暗电流的贡献.     

光伏型碲镉汞长波探测器暗电流特性的参数提取研究

报道了一种适用于碲镉汞长波光伏探测器的由典型电阻电压(R-V)曲线提取器件基本特征参数的数据处理途径.拟合程序中采用的暗电流机制包括了扩散电流机制,产生复合电流机制,陷阱辅助隧穿机制以及带到带直接隧穿电流机制.本文详细地给出了该拟合计算所采用的方法和途径,分析了拟合参数的误差范围.通过对实际器件的R-V特性曲线的拟合计算,给出了实际器件的基本特征参数,验证了该数据处理途径的实用性.     

InAs/GaSb超晶格长波红外探测器暗电流特性分析

利用二极管电流解析模型分析了InAs/GaSb超晶格长波红外探测器暗电流的主导机制。首先,通过变面积二极管I-V测试证实77 K下采用阳极硫化加SiO₂复合钝化的InAs/GaSb超晶格长波红探测器的暗电流主要来自于体电流,而非侧壁漏电流;然后,利用扩散电流、产生复合电流、直接隧穿电流和陷阱辅助隧穿电流模型对InAs/GaSb超晶格长波红外探测器的暗电流进行拟合分析。结果表明:在小的反向偏压下(≤60 mV),器件暗电流主要由产生复合电流主导,而在高偏压下(>60 mV）,器件暗电流则主要由缺陷陷阱辅助隧穿电流主导。并分析了吸收层掺杂浓度对这两种电流的影响,证实5×1015~1×1016 cm?3是优化的掺杂浓度。     

长波碲镉汞探测器RV特性分析

对硼离子注入制备的N on P平面结长波碲镉汞探测器的RV曲线进行分析,研究不同偏压下暗电流机制,提取得到探测器的电学参数及理想因子,表明为提升器件性能,需要对探测器的陷阱辅助隧穿电流及产生复合电流进行抑制。通过对长波碲镉汞探测器RV曲线的拟合分析,表明RV拟合技术作为一种有效的分析方法,可用于评估器件性能和工艺状态,并指导工艺改进。     

第二届全国先进焦平面技术研讨会论文摘要

碲镉汞二极管暗电流特性拟合参数的误差分析模型全知觉,李志锋,胡伟达,叶振华,陆卫(中国科学院上海技术物理研究所红外物理国家重点实验室,上海200083)摘要:介绍了一种分析光伏型碲镉汞器件拟合参数误差的理论模型。该模型适用于任何结构的碲镉汞同质材料形成的p-n结型光伏器件。本文以n-on-p型器件为例,详细完整地展示了该理论模型的推导和建立过程。涉及的暗电流物理模型包括了扩散电流机制、产生复合电流机制、陷阱辅助隧穿机制以及带到带直接隧穿电流机制,同时也考虑了实际器件的串联电阻效应。对真实器件拟合分析的结果表明,该模型能定…     

平面型2.6μm InGaAs 红外探测器变温特性研究

通过闭管扩散方式,在NIN型InP/In0.82Ga0.18As/InP材料上制备了单元及八元平面型红外探测器件,研究了器件的光谱响应特性、变温电流-电压特性以及器件探测率的温度响应特性。研究表明,不同温度下,在较低的偏压下,器件的正向暗电流的主要成分为源于材料缺陷的产生-复合电流,随着电压增大,器件的电流将会受到串联电阻的限制而趋于饱和。在近室温(>250 K)下,器件的反向电流主要以扩散电流和产生-复合电流为主,随着温度降低(<158 K),与偏压成正比的隧穿电流将占优势。温度>158 K时,器件的R     

MMVCX光伏型HgCdTe中波探测器暗电流温度特性

研究了光伏型HgCdTe中波探测器的暗电流与烘烤时间的关系特性.编写了一种适用于n-on-p型的中波HgCdTe红外探测器的解析拟合程序.结合暗电流的主导机制有扩散机制、产生复合机制、带间直接隧穿机制和陷阱辅助隧穿机制.通过对样品不同烘烤时间的R-V曲线的解析拟合,得到了它们的暗电流成分,提取了6个特征参数.通过对比不同烘烤时间特征参数的变化,分析了烘烤对器件的影响.     

室温下nc-Si/SiO2多层膜结构中的共振隧穿现象

采用等离子体淀积和原位氧化技术,并结合后续的热退火处理制备了nc-Si/SiO2 多层膜结构。通过电流电压特性对室温下器件中的载流子输运过程进行了表征。在正向和反向偏压下的电流电压特性曲线中都表现出了由于共振隧穿引起的负微分电导。共振隧穿产生的峰值电流对应的电压值与器件结构中的势垒层厚度相关,势垒层越厚,发生隧穿的峰值电压越高。文中通过器件的能带结构简图和等效电路图对正向、反向偏压下的共振隧穿峰值电压差异进行了细致的分析。     

离子束刻蚀HgCdTe环孔pn结I—V、RD—V特性的研究（上）

本文推导了一种可简便、准确、直观计算和分析pn结I-V特性的公式和方法,并应用该方法对两类典型HgCdTe环孔pn结的I-V、RD-V特性进行了计算和拟合;得到了表面欧姆(反型沟道)漏电导、二极管理想因子n随电压的分布等反映二极管结特性的重要参数.计算结果表明,对于长波HgCdTe光伏器件而言,表面漏电流在整个暗电流中所占的比重相当大,表面漏电流严重地制约着器件性能.HgCdTe材料的晶体缺陷会使二极管的理想因子n增大,从而使产生-复合电流及陷阱辅助隧穿电流增加.     

Temperature-dependent light-emitting characteristics of InGaN/GaN diodes

Temperature-dependent light-emitting and current-voltage characteristics of multiple-quantum well (MQW) InGaN/GaN blue LEDs were measured for temperature ranging from 100 to 500 K. The measurement results revealed two kinds of defects that have pronounced impact on the electroluminescent (EL) intensity and device reliability of the LEDs. At low-temperature (<150 K), in addition to the carrier freezing effect, shallow defects such as nitrogen vacancies or oxygen in nitrogen sites can trap the injected carriers and reduces the EL intensity. At high temperature (>300 K), deep traps due to the structure dislocations at the interfaces significantly reduce the efficiency for radiative recombination though they can enhance both forward and reverse currents significantly. In addition, the significant enhancement of trap-assisted tunneling current causes a large heat dissipation and results in a large redshift of the emission peak at high temperature.     

A model for the trap-assisted tunneling mechanism in diffused n-pand implanted n+-p HgCdTe photodiodes

A theoretical model for the trap-assisted tunneling process in diffused n-on-p and implanted n⁺-on-p HgCdTe photodiodes is presented. The model describes the connection between the leakage current associated with the traps and the trap characteristics: concentration, energy level, and capture cross sections. It was observed that the above two types of diodes differ in the voltage dependence of the trap-assisted tunneling current and dynamic resistance. The model takes this difference into account and offers an explanation of the phenomenon. The good fit between measured and calculated DC characteristics of the photodiodes (for medium and high reverse bias and for temperatures from 65 to 140 K) supports the validity of the model     

Operation of SiGe heterojunction bipolar transistors in theliquid-helium temperature regime

We present the first dc measurements of silicon-germanium (SiGe) heterojunction bipolar transistors (HBTs) operating in the liquid-helium temperature (LHeT=4.2 K) regime. The current gain of the self-aligned, UHV/CVD-grown SiGe HBT increases monotonically from 110 at 300 K to 1045 at 5.84 K, although parasitic base current leakage limits the useful operating current to above about 1.0 μA at 5.84 K. An aggressively designed base profile (peak N_AB≈8×10¹⁸ cm ^-3) is used to suppress base freeze-out at LHeT (R_bi =18.3 kΩ/□ at 4.48 K). We have also identified a non-ideal minority carrier transport mechanism in the collector current at temperatures below 77 K (I_C is not proportional to exp(qV _BE/kT)) which is unaccounted for in conventional device theory. Preliminary calculations suggest that this phenomenon is due to trap-assisted carrier tunneling from the emitter to the collector through the base potential barrier     

Measurement of Enhanced Gate-Controlled Band-to-Band Tunneling in Highly Strained Silicon-Germanium Diodes

Strained silicon-germanium (Si_0.6Ge_0.4) gated diodes have been fabricated and analyzed. The devices exhibit significantly enhanced gate-controlled tunneling current over that of coprocessed silicon control devices. The current characteristics are insensitive to measurement temperature in the 80 K to 300 K range. Independently extracted valence band offset at the strained Si_0.6Ge_0.4/Si interface is 0.4 eV, yielding a Si_0.6Ge_0.4 bandgap of 0.7 eV, which is much reduced compared to that of Si. The results are consistent with device operation based on quantum-mechanical band-to-band (BTB) tunneling rather than on thermal generation. Moreover, simulation of the strained Si_0.6Ge_0.4 device using a quantum-mechanical BTB tunneling model is in good agreement with the measurements.     

A new recombination model for device simulation including tunneling

A recombination model for device simulation that includes both trap-assisted tunneling (under forward and reverse bias) and band-to-band tunneling (Zener tunneling) is presented. The model is formulated in terms of analytical functions of local variables, which makes it easy to implement in a numerical device simulator. The trap-assisted tunneling effect is described by an expression that for weak electric fields reduces to the conventional Shockley-Read-Hall (SRH) expression for recombination via traps. Compared to the conventional SRH expression, the model has one extra physical parameter, the effective mass m*. For m*=0.25 m₀ the model correctly describes the experimental observations associated with tunneling. The band-to-band tunneling contribution is found to be important at room temperature for electric fields larger than 7×10⁵ V/cm. For dopant concentrations above 5×10¹⁷ cm^-3 or, equivalently, for breakdown voltages below approximately 5 V, the reverse characteristics are dominated by band-to-band tunneling     

钝化处理对Al2O3/InP MOS电容界面特性的影响

制备了Al/Al_2O_3/InP金属氧化物半导体(MOS)电容,分别采用氮等离子体钝化工艺和硫钝化工艺处理InP表面。研究了在150、200和300 K温度下样品的界面特性和漏电特性。实验结果表明,硫钝化工艺能够有效地降低快界面态,在150 K下测试得到最小界面态密度为1.6×10¹⁰ cm^-2·eV^-1。与硫钝化工艺对比,随测试温度升高,氮等离子体钝化工艺可以有效减少边界陷阱,边界陷阱密度从1.1×10¹² cm^-2·V^-1降低至5.9×10¹¹ cm^-2·V^-1,同时减少了陷阱辅助隧穿电流。氮等离子体钝化工艺和硫钝化工艺分别在降低边界陷阱和快界面态方面有一定优势,为改善器件界面的可靠性提供了依据。