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Toshiki ARAI Shigeharu YAMAGAMI Yoshifumi OKUDA Yoshimichi HARADA Yasuyuki MIYAMOTO Kazuhito FURUYA
Fabrication process for narrow emitter along 010 direction in heterojunction bipolar transistor fully drawn by electron beam lithography was studied. Emitter structure of a 100 nm width was formed by using epitaxial structure with 30-nm-thick InP layer of emitter. Transistor operation of devices with 0.5-µ m-wide emitter was confirmed. This process can be applied to a buried metal heterojunction bipolar transistor (BM-HBT) with narrow emitter, resulting in high-speed operation of BM-HBT.
Youichiro NIITSU Hiroyuki MIYAKAWA Osamu HIDAKA
Narrow emitter effects in self-aligned bipolar transistors are discussed. Besides the increase of a non-ideal base current, the decrease of an ideal base current is newly observed, and a consequent fluctuation of the current gain becomes wider in the smaller emitter geometry. Both phenomena are attributed to the reduction of an emitter-impurity concentration.