真空紫外连续谱的获得

本文报道了惰性气体氙、氪、氩在真空紫外波段连续发射谱的获得及其一些特性,并与国外Tanaka[1—3]等人的工作做了比较。氩、氪的最短波长可达1300A左右。其强度随放电管内所充气体压力的升高而增强。     

Physical modeling based on hydrodynamic simulation for the design of InGaAs/InP double heterojunction bipolar transistors

A physical model for scaling and optimizing InGaAs/InP double heterojunction bipolar transistors(DHBTs) based on hydrodynamic simulation is developed.The model is based on the hydrodynamic equation,which can accurately describe non-equilibrium conditions such as quasi-ballistic transport in the thin base and the velocity overshoot effect in the depleted collector.In addition,the model accounts for several physical effects such as bandgap narrowing,variable effective mass,and doping-dependent mobility at high fields.Good agreement between the measured and simulated values of cutoff frequency,f t,and maximum oscillation frequency,f max,are achieved for lateral and vertical device scalings.It is shown that the model in this paper is appropriate for downscaling and designing InGaAs/InP DHBTs.     

一种InP双异质结双极晶体管小信号物理模型及其提取方法

研究了InP双异质结双极晶体管（DHBT）的能带结构对集电极电容的影响,解决了传统方法不能准确提取InP DHBT集电极电容的问题.考虑了基极-发射极和集电极-发射极引线间的交叠电容,并从物理上区分了InP DHBT的本征电阻、外部电阻与寄生电阻,建立了一个基于物理的InP基DHBT小信号模型.同时提出了一套直接提取模型参数的方法,该方法无需引入数学优化,具有清晰的物理意义.提取的结果在很宽的偏置范围内准确地拟合了器件特性,验证了模型的准确性与提取方法的有效性. 关键词： InP双异质结双极晶体管 集电极电容 小信号模型 参数提取     

A Physics-Based Charge-Control Model for InP DHBT Including Current-Blocking Effect

We develop a physies-based charge-control lnP double hereto junction bipolar transistor model including three important effects： current blocking, mobile-charge modulation of the base-collector capacitance and velocity-field modulation in the transit time. The bias-dependent base-collector depletion charge is obtained analytically, which takes into account the mobile-charge modulation. Then, a measurement based voltage-dependent transit time formulation is implemented. As a result, over a wide range of biases, the developed model shows good agreement between the modeled and measured S-parameters and cutoff frequency. Also, the model considering current blocking effect demonstrates more accurate prediction of the output characteristics than conventional vertical bipolar inter company results.