DOUBLY STRAINED IN0.41AL0.59AS/N+-IN0.65GA0.35 AS HFET WITH HIGH BREAKDOWN VOLTAGE

An In0.41Al0.59As/n+-In0.65Ga0.35As HFET on InP was designed and fabricated, using the following methodology to enhance device breakdown: 1) a quantum-well channel to intro duce electron quantization and increase the effective channel bandgap, 2) a strained In0.41Al0.59As insulator, and 3) the elimination of parasitic mesa-sidewall gate leakage. The In0.65Ga0.35As channel is optimally doped to N(D) = 6 X 10(18) cm-3. The resulting device (L(g) = 1.9 mum, W(g) = 200 mum) has f(t) = 14.9 GHz, f(max) in the range of 85 to 101 GHz, MSG = 17.6 dB at 12 GHz, V(B) = 12.8 V, and I(D(max)) = 302 mA/mm. This structure offers the promise of high-voltage applications at high frequencies on InP.