关于晶体管最高振荡频率有关因素的测量分析

本文讨论了晶体管最高振荡频率有关因素的一种测量分析方法。利用在基极和集电极迴路中串入外加串联电阻后测量最高振荡频率的变动,可以同时获得晶体管共发射极短路电流放大零增益频率f_T、基极电阻γ_b、集电极电容C_c以及本征的特性频率f_Td。讨论了当基极层厚度调制作用所致的集电极电导起作用时的分析方法。最后分析了漂移晶体管最高振荡频率与晶体管外部参数的关系,结果说明,上述方法在考虑了适应于漂移晶体管的修正步骤后,除同样能得到f_Td、γ_b、C_c等有关参数外,还可以分析得出漂移晶体管基极层中的漂移电场强度。

ON MEASUREMENT AND ANALYSIS OF FACTORS AFFECTING THE MAXIMUM FREQUENCY OF OSCILLATION OF TRANSISTORS

A simple method to measure and analyse the factors affecting the maximum frequency of oscillation of transistors is described. From the maximum frequencies of oscillation measured with certain external series resistances connected in the base and collector circuits, the frequency of zero db current gain f_T, base resistance r_b, collector capacitance C_c, and also the intrinsic characteristic frequency f_Td of the transistor can be deduced. The method of analysis is also discussed in the case when the collector conductance introduced by base width modulation plays an important role in limiting the maximum frequency of oscillation of the transistor. The connection between the maximum frequency of oscillation of drift transistor and its external parameters is discussed finally. It is concluded that when proper corrections are made for drift transistors, not only f_Td, r_b, and C_c, but also the magnitude of drift field in the base region of drift transistors can be deduced.