A silicon heterojunction transistor

Abstract
SIPOS (Semi‐insulating polycrystalline silicon) which is used as a surface passivation layer for highly reliable silicon devices constitutes a good heterojunction for silicon. P‐ or B‐doped SIPOS has been used as the emitter material of a heterojunction transistor with the base and collector of silicon. An npn SIPOS‐Si heterojunction transistor showing 50 times the current gain of an npn silicon homojunction transistor has been realized by high‐temperature treatments in nitrogen and low‐temperature annealing in hydrogen or forming gas.