Title :
Comprehensive Study of Emitter-Ledge Thickness of InGaP/GaAs HBTs
Author :
Fu, Ssu-I ; Cheng, Shiou-Ying ; Chen, Tzu-Pin ; Lai, Po-Hsien ; Tsai, Yan-Ying ; Hung, Ching-Wen ; Yen, Chih-Hung ; Liu, Wen-Chau
Author_Institution :
Dept. of Electr. Eng., Nat. Cheng Kung Univ., Tainan
Abstract :
A comprehensive study of emitter-ledge thickness of InGaP/GaAs heterojunction bipolar transistors (HBTs) has been undertaken. It is shown that the recombination rate and electron densities are drastically increased near the exposed base surface between the base contact and the emitter ledge. In contrast, the corresponding hole densities are decreased. If the emitter ledge is too thick, current will flow through the undepleted ledge, which increases the emitter-size effect. In contrast, if the emitter ledge is too thin, it may not effectively passivate the surface. Therefore, the thickness of the emitter ledge is a crucial issue and should be carefully considered. It is shown that, from simulated and experimental results, the optimum emitter-ledge thickness of InGaP/GaAs HBT is 100-200 Aring
Keywords :
III-V semiconductors; electron density; electron-hole recombination; gallium arsenide; gallium compounds; heterojunction bipolar transistors; hole density; indium compounds; passivation; 100 to 200 Aring; InGaP-GaAs; electron density; emitter-ledge thickness; emitter-size effect; heterojunction bipolar transistors; hole density; recombination rate; surface channel; surface passivation; Analytical models; Bipolar transistors; Charge carrier processes; Cutoff frequency; Electron emission; Gallium arsenide; Heterojunction bipolar transistors; Linearity; Passivation; Spontaneous emission; Electron and hole density; emitter-ledge thickness; recombination rate; surface channel;
Journal_Title :
Electron Devices, IEEE Transactions on
DOI :
10.1109/TED.2006.883943
