An Improved In0.5Ga0.5P/GaAs Heterostructure-Emitter Bipolar Transistors Utilizing GaAs Spacers

• Main Authors: Shing-Dong Ho, 何信東
• Other Authors: Wei-Chou Hsu
• Format: Others
• Language: zh-TW
• Published: 1996
• Online Access: http://ndltd.ncl.edu.tw/handle/77964503790648095243

碩士 === 國立成功大學 === 電機工程研究所 === 84 === The conventional HBT suffers from larger offset voltage , resulting in unnecessary power consumption . In this thesis , we improve the common-emitter offset voltage by using heterostructure-emitter bipolar transistor ( HEBT ) structure which moves the heterojunction from p-n junction to the emitter region . The proposed structures exhit no potential spike at emitter-base ( E-B ) junction . Consequently , low offset voltage and no knee-shaped characteristics are achieved . The improved In0.5Ga0.5P/GaAs SHEBT and DHEBT structures with an undoped GaAs spacer layer at p-n junction are proposed. The undoped GaAs spacer is used to reduce the recombination at interface and enhance the current gain . The current gains of In0.5Ga0.5P/GaAs SHEBT and DHEBT for unpassivated devices are 200 and 120 , respectively . By using the emitter edge-thinning technique , the current gain of SHEBT and DHEBT is up to 350 and 180 , respectively . Among the reported HEBT's , the current gain of SHEBT is highest . The offset voltage of SHEBT and DHEBT are 80 and 50 mV ,respectively . The low offset voltage also indicates that no potential spike exists at E-B junction .