| 摘要 |
A multi layer semiconductor structure divided into HBT, heterojunction bipolar transistor (2) and FET, field effect transistor (3) portions with a first epitaxial structure (4) shared by the HBT and FET portions, the epitaxial structure contain layers suitable for forming the layers of a FET beneath a FET gate (5); a first etch stop layer (13) on the first epitaxial structure shared by the HBT and FET portions; a cap layer (14) on the first etch stop layer shared by the HBT and FET portions; the FET portion with an aperture (15) extending through the cap layer (14) and first etch stop layer to the first epitaxial structure; a second etch stop layer on the HBT portion of the cap layer; and a second epitaxial structure (19) on the second etch stop layer (18). The second epitaxial structure includes layers suitable for forming a portion of a HBT and can contain subcollector (20), collector (21), base (22) and emitter (24). The base can include a AlInP cover layer (23). The etch stop layers 13, 18 can be made of a AlInP in a AlxIN1-xP composition where x is in the range of 0.05 to 0.95 or 0.4 to 0.6 or have the value of 0.5. By using a material which includes both Aluminum and Phosphorous the etch stop layer can be used for both dry and wet etch fabrication methods. The FET can be a MESFET or a pseudomorphic HEMT, pHEMT with a Schottky barrier layer. |
