双极型晶体管PN结电容温度特性研究

Research on Temperature Characteristics of PN Junction Capacitance of Bipolar Transistor

以轨道电路系统中常用某型号双极型晶体管为对象,结合轨道电路系统信号特点,研究环境温度对其P N结电容的影响规律。研究发现,该款晶体管基极-发射极与基极-集电极P N结电容变化规律基本一致,即随外加电场增加P N结,电容值也随之增加,且由势垒电容逐渐向扩散电容转变。当外加电场低于内建电场时,PN结电容值随环境温度升高而增加;当外加电场高于内建电场时,PN结电容值则随环境温度升高而逐渐减小。本研究对晶体管选型、维护及故障失效分析具有实际工程价值。

In this paper,taking a commonly-used model of bipolar junction transistor as an example,the patterns of the eff ect of environmental temperature on the PN junction capacitance are investigated based on the signal features of track circuit systems.The results show that the PN junction capacitance between the base and emitter has the same variation trend as the PN junction capacitance between the base and collector.This means that as the external electric field rises,the value of the PN junction capacitance also increases,changing from barrier to diff usion capacitance.The PN junction capacitance decreases as the temperature increases when the external electric fi eld is higher than builtin fi eld.However,when the external fi eld is lower than built-in fi eld,the PN junction capacitance increases as the temperature rises.The study result is valuable to device selection,maintenance and fault analysis in practical engineering.