Gallium arsenide based device having a narrow band-gap semiconductor contact layer

摘要

A device includes a semiconductor die. The semiconductor die includes a plurality of semiconductor layers disposed on a GaAs substrate, including a first semiconductor layer having a first band-gap and a second semiconductor layer having a second band-gap. The semiconductor die further includes a contact layer disposed epitaxially upon the first semiconductor layer. The contact layer has a thickness that is less than a critical thickness. The second semiconductor layer is epitaxially disposed upon the contact layer. The contact layer has a third band-gap that is less than the first band-gap and the second band-gap. The semiconductor die further includes a conductive layer disposed upon the contact layer to form an ohmic contact. The conductive layer comprises one or more metal layers compatible with silicon processing techniques.

主权项

1. A device, comprising:
a semiconductor die that includes a heterojunction bipolar transistor (HBT) having a collector, base, and emitter, the HBT including: a plurality of semiconductor layers disposed on a gallium arsenide (GaAs) substrate, including:
a sub-collector layer having a first band-gap;a contact layer of the collector having a second band-gap that is less than the first band-gap, wherein:
the contact layer is epitaxially disposed on the sub-collector layer; andthe contact layer has a thickness less than a critical thickness, wherein the critical thickness is a thickness below which the contact layer remains epitaxial with the sub-collector layer;a collector layer of the collector having a third band-gap that is larger than the second band-gap, wherein the collector layer is epitaxially disposed on the contact layer;one or more base layers of the base epitaxially disposed upon a respective layer of the collector; andone or more emitter layers of the emitter epitaxially disposed upon a respective layer of the base; and a conductive layer disposed upon the contact layer to form an ohmic contact for the collector, wherein the conductive layer comprises one or more metal layers compatible with silicon processing techniques.