New 4H silicon carbide metal semiconductor field-effect transistor with a buffer layer between the gate and the channel layer

A new 4H silicon carbide metal semiconductor field-effect transistor (4H-SiC MESFET) structure with a buffer layer between the gate and the channel layer is proposed in this paper for high power microwave applications.The physics-based analytical models for calculating the performance of the proposed device are obtained by solving one-and two-dimensional Poisson’s equations.In the models,we take into account not only two regions under the gate but also a third high field region between the gate and the drain which is usually omitted.The direct-current and the alternatingcurrent performances for the proposed 4H-SiC MESFET with a buffer layer of 0.2 μm are calculated.The calculated results are in good agreement with the experimental data.The current is larger than that of the conventional structure.The cutoff frequency (fT) and the maximum oscillation frequency (f max) are 20.4 GHz and 101.6 GHz,respectively,which are higher than 7.8 GHz and 45.3 GHz of the conventional structure.Therefore,the proposed 4H-SiC MESFET structure has better power and microwave performances than the conventional structure.     

A novel analytical thermal model for multilevel nano-scale interconnects considering the via effect

Based on the heat diffusion equation of multilevel interconnects, a novel analytical thermal model for multilevel nano-scale interconnects considering the via effect is presented, which can compute quickly the temperature of multilevel interconnects, with substrate temperature given. Based on the proposed model and the 65~nm complementary metal oxide semiconductor (CMOS) process parameter, the temperature of nano-scale interconnects is computed. The computed results show that the via effect has a great effect on local interconnects, but the reduction of thermal conductivity has little effect on local interconnects. With the reduction of thermal conductivity or the increase of current density, however, the temperature of global interconnects rises greatly, which can result in a great deterioration in their performance. The proposed model can be applied to computer aided design (CAD) of very large-scale integrated circuits (VLSIs) in nano-scale technologies.     

Through-silicon-via crosstalk model and optimization design for three-dimensional integrated circuits

Through-silicon-via （TSV） to TSV crosstalk noise is one of the key factors affecting the signal integrity of three- dimensional integrated circuits （3D ICs）. Based on the frequency dependent equivalent electrical parameters for the TSV channel, an analytical crosstalk noise model is established to capture the TSV induced crosstalk noise. The impact of various design parameters including insulation dielectric, via pitch, via height, silicon conductivity, and terminal impedance on the crosstalk noise is analyzed with the proposed model. Two approaches are proposed to alleviate the TSV noise, namely, driver sizing and via shielding, and the SPICE results show 241 rnV and 379 mV reductions in the peak noise voltage, respectively.     

红外保护膜性能评估和分析

讨论红外保护膜的作用，分析和介绍保护膜的机械强度以及保护膜的外应力和内应力产生的破坏和影响，并提出了应对措施，探讨保护膜在恶劣环境下的光学性能，指出优化控制膜厚的重要性。     

ECRCVD技术淀积太阳电池的减反膜

本文报道了用电子回旋共振化学气相淀积(ECRCVD)技术实现了低温(50℃)淀积SiON/SiN膜作硅太阳电池减反射膜的实验研究.探讨了影响薄膜性能的主要工艺参数,设计了具有较佳抗反效果的双层减反膜,并对膜层的反射率和太阳电池参数进行了测定.结果表明:该减反膜具有良好的减反效果,能实现较宽波段范围内的均匀增透,使太阳电池短路电流密度提高了42%,电池转换效率提高了45%.     

GaN高电子迁移率晶体管强电磁脉冲损伤效应与机理

提出了一种新型GaN异质结高电子迁移率晶体管在强电磁脉冲下的二维电热模型,模型引入材料固有的极化效应,高场下电子迁移率退化、载流子雪崩产生效应以及器件自热效应,分析了栅极注入强电磁脉冲情况下器件内部的瞬态响应,对其损伤机理和损伤阈值变化规律进行了研究.结果表明,器件内部温升速率呈现出"快速-缓慢-急剧"的趋势.当器件局部温度足够高时(2000 K),该位置热电子发射与温度升高形成正反馈,导致温度急剧升高直至烧毁.栅极靠近源端的柱面处是由于热积累最易发生熔融烧毁的部位,严重影响器件的特性和可靠性.随着脉宽的增加,损伤功率阈值迅速减小而损伤能量阈值逐渐增大.通过数据拟合得到脉宽τ与损伤功率阈值P和损伤能量阈值E的关系.     

Hardening measures for bipolar transistors against microwave-induced damage

In the present paper we study the influences of the bias voltage and the external components on the damage progress of a bipolar transistor induced by high-power microwaves. The mechanism is presented by analyzing the variation in the internal distribution of the temperature in the device. The findings show that the device becomes less vulnerable to damage with an increase in bias voltage. Both the series diode at the base and the relatively low series resistance at the emitter, Re, can obviously prolong the burnout time of the device. However, Re will aid damage to the device when the value is sufficiently high due to the fact that the highest hot spot shifts from the base-emitter junction to the base region. Moreover, the series resistance at the base Rb will weaken the capability of the device to withstand microwave damage.     

考虑工艺波动的RC互连树统计功耗

为了有效分析考虑工艺波动的RC互连树统计功耗,本文首先给出了考虑工艺波动的互连寄生参数和输入驱动点导纳矩的构建方法,然后,推导得出了互连功耗均值与标准差的表达式.计算结果表明,与目前广泛应用的Monte Carlo分析方法相比,采用本文方法得到的RC互连功耗均值误差小于4.36 %,标准差误差则小于6.68 %.结果显示,本文方法在确保精度的前提下大大缩短了仿真时间. 关键词： 工艺波动 RC互连')" href="#">RC互连 统计功耗     

考虑硅通孔的三维集成电路热传输解析模型

基于不考虑硅通孔的N层叠芯片的一维热传输解析模型,提出了硅通孔的等效热模型,获得了考虑硅通孔的三维集成电路热传输解析模型,并采用Matlab软件验证分析了硅通孔对三维集成电路热管理的影响.分析结果表明,硅通孔能有效改善三维集成电路的散热,硅通孔的间距增大将使三维集成电路的温升变大. 关键词： 三维集成电路 热管理 硅通孔 等效热模型     

Steady-state and transient electronic transport properties of β-(AlxGa1-x)2O3/Ga2O3 heterostructures: An ensemble Monte Carlo simulation

The steady-state and transient electron transport properties of $\beta $-(Al$_{x}$Ga$_{1-x}$)$_{2}$O$_{3}$/Ga$_{2}$O$_{3}$ heterostructures were investigated by Monte Carlo simulation with the classic three-valley model. In particular, the electronic band structures were acquired by first-principles calculations, which could provide precise parameters for calculating the transport properties of the two-dimensional electron gas (2DEG), and the quantization effect was considered in the $\varGamma $ valley with the five lowest subbands. Wave functions and energy eigenvalues were obtained by iteration of the Schrödinger-Poisson equations to calculate the 2DEG scattering rates with five main scattering mechanisms considered. The simulated low-field electron mobilities agree well with the experimental results, thus confirming the effectiveness of our models. The results show that the room temperature electron mobility of the $\beta $-(Al$_{0.188}$Ga$_{0.812}$)$_{2}$O$_{3}$/Ga$_{2}$O$_{3}$ heterostructure at 10 kV$ \cdot$cm$^{-1}$ is approximately 153.669 cm$^{2}\cdot$V$^{-1}\cdot$s$^{-1}$, and polar optical phonon scattering would have a significant impact on the mobility properties at this time. The region of negative differential mobility, overshoot of the transient electron velocity and negative diffusion coefficients are also observed when the electric field increases to the corresponding threshold value or even exceeds it. This work offers significant parameters for the $\beta$-(Al$_{x}$Ga$_{1-x}$)$_{2}$O$_{3}$/Ga$_{2}$O$_{3}$ heterostructure that may benefit the design of high-performance $\beta$-(Al$_{x}$Ga$_{1-x}$)$_{2}$O$_{3}$/Ga$_{2}$O$_{3}$ heterostructure-based devices.