相场法模拟GaAs衬底上InGaAs异质结表面形貌

本工作采用相场法模拟GaAs衬底上生长的In_(0.3)Ga_(0.7)As多层异质结构薄膜表面。通过引入多序参量,使用半隐性傅里叶谱方法求解Cahn-Hilliard方程可以求得带缓冲层结构的薄膜表面形貌。计算结果模拟了薄膜生长过程,研究显示,使用In0.15-Ga0.85As缓冲层,厚度从1nm增加到4nm,薄膜表面临界波长从34nm提升到80nm。随着缓冲层的厚度从1nm增加到10nm,使用正弦波表面的模拟结果显示,薄膜表面粗糙度从2.87nm下降到0.43nm,随机叠加波表面的模拟结果也类似,表面粗糙度从1.21nm下降到0.18nm。热力学分析和应变分布分析可以解释缓冲层对薄膜表面形貌演化的作用。该模拟计算方式对设计缓冲层结构有很大的帮助,模拟计算的结果可以与实验相比对。     

Interface state densities, low frequency noise and electron mobility in surface channel In0.53Ga0.47As n-MOSFETs with a ZrO2 gate dielectric

This paper reports on an investigation of interface state densities, low frequency noise and electron mobility in surface channel In_0.53Ga_0.47As n-MOSFETs with a ZrO₂ gate dielectric. Interface state density values of D_it ∼ 5 × 10¹² cm⁻² eV⁻¹ were extracted using sub-threshold slope analysis and charge pumping technique. The same order of magnitude of trap density was found from low frequency noise measurements. A peak effective electron mobility of 1200 cm²/Vs has been achieved. For these surface channel In_0.53Ga_0.47As n-MOSFETs, it was found that η parameter, an empirical parameter used to calculate the effective electric field, was ∼0.55, and is to be comparable to the standard value found in Si device.     

On the mechanisms limiting mobility in InP/InGaAs buried channel nMISFETs

MISFETs incorporating the InP/InGaAs buried channel showed a high peak mobility of 5500 cm²/V s. Spillover of the inversion carriers from the buried channel to the MIS interface on the InP barrier layer caused drastic mobility degradation as the carrier concentration was increased. The spillover was evidenced by observing a negative transconductance and a kink in split capacitance-voltage curves. Remote scattering by the trapped charges at the MIS interface also reduced the mobility when the InP barrier layer was as thin as 2 nm.     

Origin of electron mobility enhancement in (1 1 1)-oriented InGaAs channel metal-insulator-semiconductor field-effect-transistors

Electrical and physical characteristics of the Al₂O₃/InGaAs interfaces with (1 1 1)A and (1 0 0) orientations were investigated in an attempt to understand the origin of electron mobility enhancement in the (1 1 1)A-channel metal-insulator-semiconductor field-effect-transistor. The (1 1 1)A interface has less As atoms of high oxidation states as probed by X-ray photoelectron spectroscopy. The electrical measurements showed that energy distribution of the interface traps for the (1 1 1)A interface is shifted toward the conduction band as compared to that for the (1 0 0) interface. Laterally-compressed cross-section transmission electron microscopy images showed that the characteristic lengths of the interface roughness are different between the (1 1 1)A and (1 0 0) interfaces. The contributions of the Coulomb and roughness scattering mechanisms are discussed based on the experimental results.     

基于InGaAs探测器的FBG传感系统数据采集研究

研究并实现了一种基于InGaAs线阵探测器的光纤Bragg光栅（FBG）传感系统。针对所采用的InGaAs线阵探测器,分析了其基本特征和工作时序,设计了相应的驱动电路和数据采集、传输系统,并基于FPGA时序控制实现了上述系统。针对系统采集得到的原始数据,通过双通道数据分离算法得到完整的光谱数据,并通过多项式拟合对数据进...     

0.15μmInGaAs PHEMT50MHz-1GHz高线性CATV放大器设计

本文对应用于CATV（有线电视）的50MHz - 1GHz频段的低噪声和高线性度单片微波集成电路（MMIC）放大器进行了设计。设计采用并联电压交流负反馈和源极电流负反馈相结合以扩大带宽和高线性度。本文引入一种新的共源共栅管基极偏置以稳定工作点来进一步提高线性度。该电路由台湾稳懋半导体公司的0.15μm InGaAs PHEMT工艺制作。测试在有线电视频段50MHz-1GHz范围内和75欧姆测试匹配系统中进行。.测试结果表明芯片小信号增益为16.5dB,带内波动小于 1dB。噪声指数在带内为1.7-2.9dB。IIP3高达16dBm。CSO和CTB分别为68dBc和77dBc。芯片面积为0.56 mm2,而功耗在5V供电下为110mA。测试结果表明芯片展现了出色的噪声性能和高线性度,非常适合于有线电视系统。     

S波段大功率GaAs PHEMT单片放大器

GaAs单片集成电路具有体积小、质量轻和可靠性高等特性,已经成为微波领域重要的器件。采用MBE技术生长出双面掺杂AlGaAs/InGaAs PHEMT结构的外延材料,研制了高效率的GaAs PHEMT器件,S波段功率附加效率大于55%。建立了基于EEHEMT的大信号模型,利用ADS软件搭建了有耗匹配的二级放大电路拓扑结构,进行最佳效率匹配,得到优化电路。采用4英寸(1英寸=2.54cm)GaAs0.35μm标准工艺研制了AlGaAs/InGaAs/GaAsPHEMT MMIC电路,测试结果表明,在测试频率为2.2~3.4GHz,测试电压VDS为10V时,输出功率大于12W,功率增益大于22dB,功率附加效率大于40%。     

基于InGaAs/InP雪崩光电二极管的高速单光子探测器雪崩特性研究

报道了一种基于InGaAs/InP雪崩光电二极管、1.25 GHz正弦波门控及贝塞尔低通滤波器的1.25 GHz高速短波红外单光子探测器.通过调整比较电路的鉴别电平, 实验研究了单光子探测器雪崩信号幅度随反向直流偏压的变化.随着鉴别电平的提高, 单光子探测器的探测效率及暗计数率均呈指数衰减, 而后脉冲概率先增大到一个峰值, 然后减小.研究表明, 为获得更高的性能, 需要尽量降低单光子探测器的鉴别电平.     

非对称In0.53Ga0.47As/In0.52Al0.48As量子阱的零场自旋分裂能与高场g因子

我们研究了非对称In_0.53Ga_0.47As/In_0.52Al_0.48As量子阱中二维电子气的磁输运性质,所测量的样品的径向磁阻Rxx的Shubinikov-de Haas振荡没有呈现出拍频的特征。通过测量样品的弱局域效应提取了其零场自旋分裂能并通过对自旋分裂的Rxx双峰间距随倾斜角度theta的依赖关系的拟合提取了高场下的有效g因子。样品的Dingle plot图呈现非线性和特征,这可以归因于来自样品衬底附近的掺杂Be原子的长程势散射效应。     

用于光子计数的InGaAs/InP SPAD设计

重点研究了InGaAs/InP SPAD的隧道贯穿电场、雪崩击穿电场、雪崩宽度与过偏电压的关系,提出了过偏电压的计算方法.分析了InGaAs/InP SPAD的基本特性即探测效率、暗计数率与其过偏电压、工作温度、量子效率、电场分布的依赖关系,提出了一种单光子InGaAs雪崩二极管的设计方法.设计制作了InGaAs/InP SPAD,并在门控淬灭模式下进行了单光子探测实验.结果表明:对于200m的SPAD,在过偏2 V、温度-40 ℃条件下,探测效率(PDE) 20%(1 550 nm)、暗计数率(DCR)20 kHz;对于50m的SPAD,在过偏2.5 V、温度-40 ℃条件下,探测效率(PDE) 23%(1 550 nm)、暗计数率(DCR)2 kHz.最后对实验结果进行了分析和讨论.