Title :
Self-consistent particle simulation for (AlGa)As/GaAs HBTs under high bias conditions
Author :
Katoh, Riichi ; Kurata, Mamoru
Author_Institution :
Toshiba Corp., Kawasaki, Japan
fDate :
10/1/1989 12:00:00 AM
Abstract :
Nonequilibrium electron transport phenomena in the emitter and collector regions under high bias conditions were investigated for standard N-p-n (AlGa)As/GaAs heterojunction bipolar transistors (HBTs) by utilizing a previously developed one-dimensional self-consistent particle simulator. A dramatic increase in the cutoff frequency was observed for a lightly doped collector HBT as the current density increased over 105 A/cm2, where the collector transit time was reduced due to the extension of the velocity overshoot region in the collector corresponding to the decrease in electric field near onset of the Kirk effect. A saturation tendency was seen in the collector current versus base-to-emitter bias voltage (VBE ) characteristic for high VBE, where VBE exceeded the base-to-emitter built-in voltage of the conduction band. Simulations indicate that this feature is caused by electron velocity saturation in the neutral n-type (AlGa)As emitter region
Keywords :
III-V semiconductors; aluminium compounds; gallium arsenide; heterojunction bipolar transistors; high field effects; semiconductor device models; AlGaAs-GaAs; HBTs; I-V characteristics; Kirk effect; base-to-emitter bias voltage; collector current; collector transit time; current density; cutoff frequency; electron velocity saturation; heterojunction bipolar transistors; high bias conditions; lightly doped collector HBT; nonequilibrium electron transport; one-dimensional self-consistent particle simulator; velocity overshoot region; Current density; Electron emission; Equations; Gallium arsenide; Helium; Heterojunction bipolar transistors; Kirk field collapse effect; Semiconductor materials; Standards development; Voltage;
Journal_Title :
Electron Devices, IEEE Transactions on