Development of a Planar Heterojunction Bipolar Transistor for Very High Speed Logic.
Annual technical rept. no. 3, 1 Oct 84-1 Mar 86,
CALIFORNIA UNIV SANTA BARBARA DEPT OF ELECTRICAL AND COMPUTER ENGINEERING
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The following report describes the results of research on III-V molecular bm epitaxial MBE growth, material characterization and the fabrication of heterostructure bipolar transistors HBT for very high speed logic applications. During the reporting period work on the InGaPGaAs heterojunction HJ was completed. Isotype HJs were grown and evaluated by a CV reconstruction method in order to determine the energy band. offsets. It was found that Ec0.21 eV and Ev0.25 eV for the lattice matched composition. A new direction toward improvement in performance and the fabrication techniques for the AlGaAsGaAs HBT was successfully demonstrated. Graded-bandgap nonalloyed ohmic contacts using n InAs and GaAs for the AlGaAs emitter and p GaSb for the GaAs base were provided by selective epitaxial regrowth. The MBE growth conditions for grading from GaAs to InAs to GaSb were determined. Low specific contact resistances were observed for both contact types. A AlGaAsGaAs graded-gap contact HBT was grown. A current gain of 20 was measured with only simple wire probes on the base and emitter.
- Solid State Physics