| abstract |
A highly uniform, planar and high speed JHEMT-HBT MMIC (20) is fabricated using a single growth process. A multi-layer structure including a composite emitter-channel layer, a base-gate layer and a collector layer is grown on a substrate (26). The composite emitter-channel layer (30) includes a sub-emitter/channel layer that reduces the access resistance to the HBT's emitter (34) and the JHEMT's channel (42), thereby improving the HBT's high frequency performance and increasing the JHEMT's current gain. The multi-layer structure is then patterned and metallized to form an HBT collector contact (52, 54, 56), planar HBT base (46, 50) and JHEMT gate (48, 51) contacts, and planar HBT emitter (34) and JHEMT source (36) and drain (38) contacts. |