Title :
Extremely small emitter (1*1 mu m/sup 2/) AlGaAs/GaAs HBT´s utilizing bridged base electrode structure
Author :
Nagata, N. ; Nakajima, O. ; Nittono, T. ; Yamauchi, Y. ; Ishibashi, T.
Author_Institution :
NTT, Kanagawa, Japan
Abstract :
A novel self-aligned structure for AlGaAs-GaAs HBTs (heterojunction bipolar transistors) with extremely small emitter sizes is presented. This structure, utilizing a bridged base electrode, successfully reduces the emitter size to 1*1 mu m/sup 2/. Despite the fact that current gain is reduced as the emitter size decreases, a current gain of more than 10 is obtained in a 1*1 mu /sup 2/ emitter HBT. In high-frequency characteristics measurements, the highest values of f/sub T/=90 GHz and f/sub max/=63 GHz are obtained in a 1*5 mu m/sup 2/ emitter HBT. The realization of a 1*1 mu m/sup 2/ emitter HBT and excellent high-frequency characteristics demonstrate the effectiveness of the proposed HBT structure.<>
Keywords :
III-V semiconductors; aluminium compounds; gallium arsenide; heterojunction bipolar transistors; high-frequency effects; solid-state microwave devices; 63 GHz; 90 GHz; AlGaAs-GaAs; HBTs; bridged base electrode; current gain; emitter size; high-frequency characteristics; high-frequency characteristics measurements; Capacitance; Electrodes; Epitaxial layers; Etching; Fabrication; Frequency conversion; Gallium arsenide; Heterojunction bipolar transistors; Ohmic contacts; Power dissipation;
Conference_Titel :
Electron Devices Meeting, 1989. IEDM '89. Technical Digest., International
Conference_Location :
Washington, DC, USA
Print_ISBN :
0-7803-0817-4
DOI :
10.1109/IEDM.1989.74303
