Title :
Effect of hot-electron injection of high-frequency characteristics of abrupt In0.52(Ga1-xAlx)0.48 As/InGaAs HBT´s
Author :
Fukano, Hideki ; Nakajima, Hiroki ; Ishibashi, Tadao ; Takanashi, Yoshifumi ; Fujimoto, Masatomo
Author_Institution :
NTT Optoelectron. Lab., Kanagawa, Japan
fDate :
3/1/1992 12:00:00 AM
Abstract :
The effect of hot-electron injection energy (Ei) into the base on the high-frequency characteristics of In0/52(Ga1-xAlx)0.48 As/InGaAs abrupt heterojunction bipolar transistors (HBTs) is investigated by changing the composition of the emitter. There exists an optimum Ei at which a maximum current gain cutoff frequency (ft) is obtained. Analysis of hot-electron transport in the base and collector by Monte Carlo simulation is carried out to understand the above phenomenon. The collector transit time (τc ) increases with Ei, because electrons with higher energy transfer from the Γ valley into the upper L and X valleys. At first, the base transit time (τb ) decreases with Ei at the low Ei region. However, τb does not decrease monotically with Ei, because of the nonparabolicity in the energy-band structure of InGaAs. Consequently, there exists a minimum in the sum of τb and τc , in other words a maximum ft, at an intermediate value of Ei
Keywords :
III-V semiconductors; Monte Carlo methods; aluminium compounds; gallium arsenide; heterojunction bipolar transistors; indium compounds; semiconductor device models; HBTs; In0.52(Ga1-xAlx)0.48 As-InGaAs; Monte Carlo simulation; abrupt heterojunction; base transit time; collector transit time; current gain cutoff frequency; heterojunction bipolar transistors; high-frequency characteristics; hot-electron injection energy; hot-electron transport; semiconductors; Cutoff frequency; Electron emission; Energy exchange; Gallium arsenide; Heterojunction bipolar transistors; Indium compounds; Indium gallium arsenide; Indium phosphide; Laboratories; Secondary generated hot electron injection;
Journal_Title :
Electron Devices, IEEE Transactions on
