门极换流晶闸管透明阳极的机理与特性分析

通过分析门极换流晶闸管（GCT）透明阳极的电流输运过程，研究了透明阳极的机理，导出 了透明阳极电子电流密度的表达式.并利用MEDICI软件对GCT的开关特性进行了模拟，验证了 理论分析的正确性.另外，将GCT与具有普通阳极的门极可关断晶闸管（GTO）进行比较，分 析了透明阳极的特性，结果表明将透明阳极与缓冲层结合使用，可以更好地协调GCT的阻断 特性、通态特性及开关特性之间的矛盾，从而有效地改善GCT的综合特性.结论得到了实验结 果的证实. 关键词： 透明阳极 电力半导体器件 门极换流晶闸管 注入效率     

Experimental study of surface crystallization on integrated circuit chips

A surface crystallization phenomenon on bonding pads and wires of integrated circuit chip is reported in this paper. Through a lot of experiments, an unknown failure effect caused by mixed crystalline matter is revealed, whereas non-plasma fluorine contamination cannot cause the failure of bonding pads. By experiments combined with infrared spectroscopy analysis, the surface crystallization effect is studied. The conclusion of the study can provide the guidance for IC fabrication, modelling and analysis.     

大功率低功耗快速软恢复SiGeC功率开关二极管

为满足电力电子电路对功率开关二极管高频化的发展要求，提出了一种大功率低功耗快速软恢复p⁺(SiGeC)-n^--n⁺异质结二极管.与常规的Si p-i-n二极管相比，在正向电流密度不超过1000 A/cm²情况下，p⁺(SiGeC)-n^--n⁺二极管的正向压降减少了约1/5，有效降低了器件的通态功耗；反向恢复时间缩短了一半多，反向峰值电流降低了约25%，软 关键词： 快速软恢复 大功率低功耗 SiGeC/Si异质结功率二极管     

A novel type of ultra fast and ultra soft recovery SiGe/Si heterojunction power diode with an ideal ohmic contact

A novel type of p^+(SiGe)－n^-－n^+ heterojunction switching power diode with high-speed capability is presented to overcome the drawbacks of existing power diodes. The improvement is achieved by using a p^+－n^+ mosaic layer as a substitute for the n^+ region in the conventional p^+(SiGe)－n^-－n^+ diode to realize an `ideal ohmic' contact for electrons and holes simultaneously. Compared with conventional p^+(SiGe)－n^-－n^+ diodes, the ideal ohmic contact p^+(SiGe)－n^-－n^+ diodes have about one third of the reverse recovery time and a half of peak reverse recovery current. Furthermore, the softness factor increases nearly two times and the leakage current decreases 1－2 orders of magnitude. These improvements are achieved without resorting special process step to lower the carrier lifetime and thus the devices could be easily integrated into power ICs. The Ge percentage content of p^+(SiGe) layer is an important parameter for the optimal device design.     

An oxide filled extended trench gate super junction MOSFET structure

This paper proposes an oxide filled extended trench gate super junction (SJ) MOSFET structure to meet the need of higher frequency power switches application. Compared with the conventional trench gate SJ MOSFET, new structure has the smaller input and output capacitances, and the remarkable improvements in the breakdown voltage, on-resistance and switching speed. Furthermore, the SJ in the new structure can be realized by the existing trench etching and shallow angle implantation, which offers more freedom to SJ MOSFET device design and fabrication.     

高压IGBT雪崩鲁棒性的研究

随着绝缘栅双极晶体管(insulated gate bipolar transistor, IGBT)电压等级的提升和电流容量的增大,雪崩效应已成为限制器件安全工作区(safe operating area, SOA)的重要因素.雪崩发生后IGBT背面p+n结的空穴注入是其雪崩效应区别于其他器件的主要特征.本文通过理论分析与数值模拟的方法研究了IGBT雪崩击穿特性以及雪崩产生电流丝的性质,揭示了控制雪崩产生电流丝性质的物理机制.结果表明IGBT背面的空穴注入导致其雪崩击穿曲线上产生额外的负微分电阻分支;器件共基极电流增益α_pnp是决定雪崩产生电流丝的关键因素,随着α_pnp的增大,雪崩产生的电流丝强度越强、移动速度越慢,从而导致器件的雪崩鲁棒性越弱.