Title :
Reliability of SiGe HBTs for Power Amplifiers—Part II: Underlying Physics and Damage Modeling
Author :
Cheng, Peng ; Grens, Curtis M. ; Cressler, John D.
Author_Institution :
Georgia Inst. of Technol., Atlanta, GA, USA
Abstract :
This paper presents the underlying physics and modeling of aggressively biased cascode SiGe heterojunction bipolar transistor power amplifier (PA) cores under large-signal operating conditions. The damage characteristics observed during RF operation, particularly the base leakage and collector-base (CB) junction failure, are investigated in detail using dc stress methods. Base leakage was characterized across geometry, voltage, and current conditions, and a damage model is purposed based on Shockley-Read-Hall theory and the reaction-diffusion equation. This model is used to predict damage under aggressive RF operations, in order to extract the operational lifetime of SiGe PAs. The onset of CB junction failure was modeled using the current-gain collapse model, and it accurately captures the failure threshold current I Fail observed during RF stress.
Keywords :
Ge-Si alloys; heterojunction bipolar transistors; power amplifiers; reaction-diffusion systems; semiconductor device models; semiconductor device reliability; Shockley-Read-Hall theory; SiGe; SiGe HBT; collector-base junction failure; current-gain collapse model; damage modeling; dc stress methods; heterojunction bipolar transistor; operational lifetime; power amplifiers; reaction-diffusion equation; reliability; Base leakage; RF stress; Shockley–Read–Hall (SRH); SiGe; heterojunction bipolar transistors (HBTs); lifetime; mixed-mode stress; pinch-in; power amplifier (PA); reaction–diffusion (R–D); reliability; stress damage;
Journal_Title :
Device and Materials Reliability, IEEE Transactions on
DOI :
10.1109/TDMR.2009.2025151
