Design and Performance of Intergate-Channel-Connected Multi-Gate pHEMT for Antenna Switch

Conventional multi-gate pseudomorphic high-electron-mobility transistors (pHEMTs) in the off-state generate larger distortion than single-gate pHEMTs in RF switch applications. To reduce the distortion, the intergate region of multi-gate pHEMTs must be connected to the source and drain with resistors to be biased at the same DC voltage. The intergate region of multi-gate pHEMTs is too small to have an external electrical contact, so intergate-channel-connected pHEMTs (IGCC-pHEMTs) have been developed. IGCC-pHEMTs have a meander gate structure, where one side of the gate is connected to a metal wire layer, and the other is applied for an intergate region contact that does not widen the distance between the gates. A single-pole double-throw (SPDT) switch with IGCC-pHEMTs was fabricated by using a standard 0.5µm InGaAs pHEMT process. A SPDT switch with IGCC-pHEMTs is confirmed to have almost same small-signal properties and generate lower distortions.