Analysis of an InP/InGaAs/InP DHBT with Composite Doping Collector
带有复合掺杂层集电区的InP/InGaAs/InP DHBT直流特性分析

A novel InP/InGaAs/InP double heterojunction bipolar transistor (DHBT) structure is designed,in which a thin heavily doped n+-InP layer between the base and the collector is used to eliminate the energy spike at the B-C junction and overcome the electron blocking effect.The dependence of the effective barrier spike at the B-C junction and the I-V characteristics of the DHBT on the thickness and doping density of the n+-InP composite collector are analyzed theoretically.The results show that the device performance is optimal when the doping density is 3E19cm-3 and the thickness is 3nm for the n+-InP composite collector.The InP/InGaAs/InP DHBTs with composite doping collector are grown by gas source molecular beam epitaxy (GSMBE).The DC characteristics of the devices demonstrate that the InP/InGaAs/InP DHBT designed here effectively eliminates the energy spike at the B-C junction and improves the device performance.