Title :
High-reliability GaAs-AlGaAs HBTs by MBE with Be base doping and InGaAs emitter contacts
Author :
Streit, Dwight C. ; Oki, Aaron K. ; Umemoto, Donald K. ; Velebir, J.R. ; Stolt, K.S. ; Yamada, F.M. ; Saito, Y. ; Hafizi, Majid E. ; Bui, S. ; Tran, Liem T.
Author_Institution :
TRW, Redondo Beach, CA, USA
Abstract :
The authors have developed a modified MBE growth process to produce high-gain n-p-n GaAs-AlGaAs heterojunction bipolar transistors (HBTs) with a mean time to failure (MTTF) of 1.5*10/sup 8/ h at 125 degrees C. Beryllium incorporation and diffusion are controlled through a combination of reduced substrate temperature and increased As/Ga flux ratio during MBE growth, resulting in extremely stable HBT profiles. The authors also demonstrate graded InGaAs surface layers with nonalloyed refractory metal contacts that significantly improve ohmic reliability compared to alloyed AuGe contacts. The ability to produce robust HBTs by MBE is critically important to this technology.<>
Keywords :
III-V semiconductors; aluminium compounds; gallium arsenide; heterojunction bipolar transistors; molecular beam epitaxial growth; reliability; semiconductor doping; semiconductor growth; 1.5*10/sup 8/ h; 125 degC; As/Ga flux ratio; Be base doping; GaAs-AlGaAs; GaAs:Be; InGaAs emitter contacts; MBE growth; diffusion; heterojunction bipolar transistors; high reliability; mean time to failure; n-p-n HBT; ohmic reliability; reduced substrate temperature; refractory metal contacts; stable HBT profiles; Bipolar transistors; Doping; Gallium arsenide; Heterojunction bipolar transistors; Indium gallium arsenide; Molecular beam epitaxial growth; P-n junctions; Plasma temperature; Robustness; Substrates;
Journal_Title :
Electron Device Letters, IEEE
