Title :
Use of surface passivation ledges and local negative feedback to reduce amplitude modulation noise in AlGaAs/GaAs heterojunction bipolar transistors
Author :
Costa, Damian ; Khatibzadeh, Ali
Author_Institution :
Central Res. Labs., Texas Instrum. Inc., Dallas, TX, USA
Abstract :
It is shown that the use of surface passivation ledges and local negative feedback with an unbypassed emitter resistance reduce the AM noise of AlGaAs/GaAs heterojunction bipolar transistors (HBT´s). The simultaneous use of both techniques improves the AM noise by 9 dB at 100 Hz offset. The correspondence between reductions in baseband noise and AM noise are described.<>
Keywords :
III-V semiconductors; aluminium compounds; amplitude modulation; feedback; gallium arsenide; heterojunction bipolar transistors; passivation; semiconductor device noise; solid-state microwave devices; AM noise reduction; AlGaAs-GaAs; HBT; amplitude modulation noise; baseband noise; heterojunction bipolar transistors; local negative feedback; surface passivation ledges; unbypassed emitter resistance; Amplitude modulation; Circuit noise; Gallium arsenide; Heterojunction bipolar transistors; Negative feedback; Noise level; Noise measurement; Noise reduction; Passivation; Surface resistance;
Journal_Title :
Microwave and Guided Wave Letters, IEEE
