A new InP-InGaAs HBT with a superlattice-collector structure |
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Authors: | Jing-Yuh Chen Der-Feng Guo Shiou-Ying Cheng Kuan-Ming Lee Chun-Yuan Chen Hung-Ming Chuang Ssu-Yi Fu Wen-Chau Liu |
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Affiliation: | Dept. of Electr. Eng., Nat. Cheng-Kung Univ., Tainan, Taiwan; |
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Abstract: | The dc characteristics of an interesting InP-InGaAs heterojunction bipolar transistor (HBT) with a superlattice (SL) structure incorporated in the base-collector (B-C) junction are demonstrated. In the SL structure, holes injected from the collector collide with holes confined in the SL and impact them out of the SL across the valence-band discontinuities. With a collector-emitter (C-E) voltage V/sub CE/ less than the C-E breakdown voltage BV/sub CE0/, the current gain can be increased at base-current inputs because the released holes from the SL inject into the base to cause the emitter-base junction operating under more forward-biased condition. An ac current gain up to 204 is obtained. At base-emitter voltage V/sub BE/ inputs, the released holes travel to the base terminal to decrease the base current. The studied HBT exhibits common-emitter current gains exceeding 47 at low current levels and useful gains spreading over seven orders of magnitude of collector current. |
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