Characteristics of siliconn+-n--n+ diode with sub-micrometer n- region

In this paper, the I-V characteristics of silicon n⁺-n ^--n⁺ diode are investigated as a parameter of the length of the n^- region. This diode with shorter n^- region than 1 μm has the ohmic characteristics until reaching high electric field in spite of the existence of numerous space-charges in the n^- region, for the first time in this report. This conductance of the diode is inversely proportional to the third power of the length of the n^- region. The experimental results are in good agreement with an analytical calculation including the diffusion term of carriers injected from the n+ regions to the n^- region. However, the diode with longer n^- region than 2 μm shows the space-charge-limited conduction which is the same as earlier reports     

功率二极管反向恢复特性模拟研究

针对功率二极管反向恢复既快又软的开关特性要求,根据Rajapakse．二极管反向恢复模型,模拟二极管反向恢复I-t、V-t变化规律,模拟结果与已有文献结果吻合,通过控制变量得到不同存储时间trra、恢复时间trrb、正向电流If、正向电流上升速率dIf/dt对反向恢复电流的影响,模拟结果表明：trra,trrb跟二极管反向恢复过程密切相关。文中最后分析计算了不同电压,不同电流下二极管反向恢复过程中的功率损耗。     

Reduction of p+-n+ junction tunneling currentfor base current improvement in Si/SiGe/Si heterojunction bipolartransistors

The authors report a three-order-of-magnitude reduction in parasitic tunneling current at heavily doped p⁺-n⁺ Si/Si and SiGe/Si junctions grown by rapid thermal epitaxial chemical vapor deposition (CVD) compared with previously reported results in Si junctions fabricated by ion implantation. These results demonstrate the high quality of the epitaxial interface. The low tunneling currents allow higher limits to transistor base and emitter doping levels, yielding higher gains, reduced bias resistances, and higher Early voltages for scaled bipolar devices as well as Si/SiGe/Si heterojunction bipolar transistors     

4H-SiC trench MOSFET with an integrated Schottky barrier diode and L-shaped P+ shielding region

A novel 4H-SiC trench MOSFET is presented and investigated by simulation in this paper. The device features an integrated Schottky barrier diode and an L-shaped P⁺ shielding region beneath the gate trench and aside one wall of the gate trench (S-TMOS). The integrated Schottky barrier diode works as a free-wheeling diode in reverse recovery and reverse conduction, which significantly reduces reverse recovery charge (Q_rr) and reverse turn-on voltage (V_F). The L-shaped P⁺ region effectively shields the coupling of gate and drain, resulting in a lower gate–drain capacitance (C_gd) and date–drain charge (Q_gd). Compared with that of conventional SiC trench MOSFET (C-TMOS), the V_F and Q_rr of S-TMOS has reduced by 44% and 75%, respectively, with almost the same forward output current and reverse breakdown voltage. Moreover, the S-TMOS reduces Q_gd and C_gd by 32% and 22%, respectively, in comparison with C-TMOS.     

Near state-of-the-art power in p+-n-n+D-band IMPATT diode on a wafer with ramped n-n+interface

Fabrication of near state-of-the-art (P0= 110 mW, η = 4.85 percent p⁺-n-n⁺D band (f = 124 GHz) Si IMPATT diode on a wafer with ramped n-n⁺interface is described. Introduction of a critical annealing step, prior to p⁺diffusion, in the fabrication sequence of the diode has been found to yield the above results. Possible reasons for power and efficiency enhancement has been discussed.     

SiGeC/Si功率二极管的数值模拟与分析

将SiGeC技术应用于功率半导体器件的特性改进,提出了一种新型p (SiGeC)-n--n 异质结功率二极管结构.在分析SiGeC合金材料物理特性的基础上,给出了该结构的关键物理参数模型,并在此基础上利用MEDICI模拟,对比分析了C的引入对器件各种电特性的影响.此外,还模拟比较了不同p 区厚度对器件反向漏电流的影响.结果表明:在SiGe/Si功率二极管中加入少量的C,在基本不影响器件正向I-V特性和反向恢复特性的前提下,大大减少了器件的反向漏电流,并且C的加入还减小了器件特性对材料临界厚度的依赖性,提高了器件稳定性.     

SiGeC/Si功率二极管的数值模拟与分析

将SiGeC技术应用于功率半导体器件的特性改进,提出了一种新型p+(SiGeC)-n--n+异质结功率二极管结构.在分析SiGeC合金材料物理特性的基础上,给出了该结构的关键物理参数模型,并在此基础上利用MEDICI模拟,对比分析了C的引入对器件各种电特性的影响.此外,还模拟比较了不同p+区厚度对器件反向漏电流的影响.结果表明:在SiGe/Si功率二极管中加入少量的C,在基本不影响器件正向I-V特性和反向恢复特性的前提下,大大减少了器件的反向漏电流,并且C的加入还减小了器件特性对材料临界厚度的依赖性,提高了器件稳定性.     

一种新型n-区多层渐变掺杂SiGe/Si功率开关二极管

n^-区掺杂浓度采用多层渐变式结构的p^ (SiC．e)-n^--n^ 异质结功率二极管。对该新结构的反向恢复特性及正反向I-V特性进行了模拟,从器件运行机理上对模拟结果做出了详细的分析。与n^-区固定掺杂的普通p^ (SiGe)-n^--n^ 二极管相比。在正向压降基本不发生变化的前提下,渐变掺杂后的器件反向恢复时间可缩短一半,反向峰值电流能降低33％,反向恢复软度因子可提高1．5倍。并且,随着n^-区渐变掺杂的层数增多,反向恢复特性越好。     

具有深p 调整区的高压FSRD动态雪崩机理分析

本文利用ISE软件研究了具有深p 调整区的高压快速软恢复二极管(FSRD),重点分析了反向恢复机理和特性,导出了其电场梯度表达式,并通过仿真结果得以验证。结果表明,与参考二极管相比,新FSRD可明显地增加反向恢复软度,抑制阴极侧nn-结的峰值电场,并提高抗动态雪崩能力。     

一种新型渐变掺杂理想欧姆接触SiGeC/Si功率二极管

将新器件结构与新型半导体材料相结合,提出了一种新型的n-区三层渐变掺杂理想欧姆接触型p (SiGeC)-n-n 异质结功率二极管,并对n-区的杂质分布梯度进行了优化.基于MEDICI,给出了该结构的关键物理参数模型,并在此基础上对新结构的设计思路和工作原理进行了全面分析.结果表明,与常规理想欧姆接触结构相比,该新结构在保持快而软反向恢复特性的前提下,反向阻断电压增加了近一倍,而且正向通态特性也有所改善,很好地实现了功率二极管中Qs-Vf-Ir三者的良好折中.     

一种新型渐变掺杂理想欧姆接触SiGeC/Si功率二极管

将新器件结构与新型半导体材料相结合,提出了一种新型的n-区三层渐变掺杂理想欧姆接触型p+(SiGeC)-n-n+异质结功率二极管,并对n-区的杂质分布梯度进行了优化.基于MEDICI,给出了该结构的关键物理参数模型,并在此基础上对新结构的设计思路和工作原理进行了全面分析.结果表明,与常规理想欧姆接触结构相比,该新结构在保持快而软反向恢复特性的前提下,反向阻断电压增加了近一倍,而且正向通态特性也有所改善,很好地实现了功率二极管中Qs-Vf-Ir三者的良好折中.     

Ar+激光诱导湿刻Si的特性研究

利用聚焦的Ar+激光束诱导的方法,实现了对浸入HF:H2O(1:20)腐蚀液中的N型单晶Si样品的腐蚀,证明这种湿刻过程是一种由光生电子-空穴对引起的电化学腐蚀,腐蚀坑具有侧壁平滑的高斯状结构。腐蚀特性与入射激光功率以及Si掺杂浓度有关。应用激光诱导无电极电化学腐蚀电路模型对实验结果进行了合理的解释。     

Potential of asymmetrical Si/Ge and Ge/Si based hetero-junction transit time devices over homo-junction counterparts for generation of high power

Static and dynamic properties of both complementary n-Ge/p-Si and p-Ge/n-Si hetero-junction Double-Drift IMPATT diodes have been investigated by an advanced and realistic computer simulation technique,developed by the authors,for operation in the Ka-,V- and W-band frequencies.The results are further compared with corresponding Si and Ge homo-junction devices.The study shows high values of device efficiency,such as 23%, 22%and 21.5%,for n-Ge/p-Si IMPATTs at the Ka,V and W bands,respectively.The peak device negative conductances for n-Si/p-Ge and n-Ge/p-Si hetero-junction devices found to be 50.7×10~6 S/m~2 and 71.3×10~6 S/m~2, which are～3-4 times better than their Si and Ge counterparts at the V-band.The computed values of RF power-density for n-Ge/p-Si hetero-junction IMPATTs are 1.0×10~9,1.1×10~9 and 1.4×10~9 W/m~2,respectively,for Ka-,V- and W-band operation,which can be observed to be the highest when compared with Si,Ge and n-Si/p-Ge devices.Both of the hetero-junctions,especially the n-Ge/p-Si hetero-junction diode,can thus become a superior RF-power generator over a wide range of frequencies.The present study will help the device engineers to choose a suitable material pair for the development of high-power MM-wave IMPATT for applications in the civil and defense-related arena.     

两种新结构SiGe/Si功率二极管特性模拟

提出了在 n- 区中采用掺杂浓度三层渐变式结构 Si Ge/Si功率二极管及台面结构的 Si Ge/Si功率二极管。由 Medici模拟所得的特性表明 ,在采用 n- 区渐变掺杂结构的 p+ ( Si Ge) -n- -n+ 功率二极管中 ,在正向特性基本不发生变化的前提下 ,与 n-区固定掺杂结构相比反向恢复过程加快 ,二极管下降时间 t A 缩短近 1 /2 ;在采用台面结构的 p+ ( Si Gi) -n- -n+功率二极管中 ,反向恢复特性也有明显改进 ,电流反向恢复时间缩短近 1 /3 ,而电压反向恢复时间缩短近 1 /2。     

Fabrication of high-Ge-fraction strained Si1−xGex/Si hole resonant tunneling diode using low-temperature Si2H6 reaction for nanometer-order ultrathin Si barriers

Low-temperature Si barrier growth with atomically flat heterointerfaces was investigated in order to improve negative differential conductance (NDC) characteristics of high-Ge-fraction strained Si_1−xGe_x/Si hole resonant tunneling diode with nanometer-order thick strained Si_1−xGe_x and unstrained Si layers. Especially to suppress the roughness generation at heterointerfaces for higher Ge fraction, Si barriers were deposited using Si₂H₆ reaction at a lower temperature of 400 °C instead of SiH₄ reaction at 500 °C after the Si_0.42Ge_0.58 growth. NDC characteristics show that difference between peak and valley currents is effectively enhanced at 11-295 K by using Si₂H₆ at 400 °C, compared with that using SiH₄ at 500 °C. Non-thermal leakage current at lower temperatures below 100 K tends to increase with decrease of Si barrier thickness. Additionally, thermionic-emission dominant characteristics at higher temperatures above 100 K suggests a possibility that introduction of larger barrier height (i.e. larger band discontinuity) enhances the NDC at room temperature by suppression of thermionic-emission current.     

高峰谷电流比的高掺杂发射区In0.53Ga0.47As/AlAs共振隧穿二极管

利用空气桥工艺设计和制作了高掺杂发射区In0.53Ga0.47As/AlAs共振隧穿二极管（RTD）。在室温下,器件的峰谷电流比大于40,峰值电流密度为24kA/cm2。建立了RTD器件等效电路模型,并从直流和微波测试结果中提取出器件参数。高峰谷电流比的RTD器件具有非常小的电容,有利于在微波/太赫兹领域中的应用。