The Role of the Silicon Germanium (SiGe) Heterojunction Bipolar Transistor (HBT) in Mobile Technology Platforms

2011 ◽  
Author(s):  
Gregory A. Mitchell
Keyword(s):  
Mobile Technology ◽  
Silicon Germanium ◽  
Bipolar Transistor ◽  
Heterojunction Bipolar Transistor ◽  
Technology Platforms

Zinc Diffusion in GaAs-AIGaAs Heterojunction Bipolar Transistor Structures

1990 ◽  
Vol 198 ◽  
Author(s):  
W. S. Hobson ◽  
S. J. Pearton ◽  
A. S. Jordan
Keyword(s):  
Surface Layer ◽  
Bipolar Transistor ◽  
Recent Model ◽  
Heterojunction Bipolar Transistor ◽  
Organometallic Vapor Phase Epitaxy ◽  
Base Region ◽  
Zn Diffusion ◽  
Si Doping ◽  
Zinc Diffusion

ABSTRACTWe have examined the diffusion of Zn from the base of GaAs-AIGaAs heterojunction bipolar transistor (HBT) structures during growth by organometallic vapor phase epitaxy. The role of Si doping in the emitter-contact, emitter, and collector/subcollector in enhancing the Zn diffusion has been determined by separately doping each layer. For a growth temperature of 675°C Zn shows no observable redistribution up to concentrations of 3x1019 cm−3 without Si doping. The addition of Si to the adjacent AIGaAs emitter and GaAs collector/subcollector layers causes significant diffusion from the base, while Si doping of the GaAs emitter-contact results in even greater Zn redistribution. Silicon counter-doping in the base region retards the Zn diffusion. These results are consistent with a recent model which shows that the n-type surface layer enhances the formation of gallium interstitials which diffuse into the structure and displace the Zn in the base via a kick-out mechanism.

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