Doubly strained In/sub 0.41/Al/sub 0.59/As/n/sup +/-In/sub 0.65/Ga/sub 0.35/As HFET with high breakdown voltage

An In/sub 0.41/Al/sub 0.59/As/n/sup +/-In/sub 0.65/Ga/sub 0.35/As HFET on InP was designed and fabricated, using the following methodology to enhance device breakdown: a quantum-well channel to introduce electron quantization and increase the effective channel bandgap, a strained In/sub 0.41/Al/sub 0.59/As insulator, and the elimination of parasitic mesa-sidewall gate leakage. The In/sub 0.65/Ga/sub 0.35/As channel is optimally doped to N/sub D/=6*10/sup 18/ cm/sup -3/. The resulting device (L/sub g/=1.9 mu m, W/sub g/=200 mu m) has f/sub t/=14.9 GHz, f/sub max/ in the range of 85 to 101 GHz, MSG=17.6 dB at 12 GHz V/sub B/=12.8 V, and I/sub D(max)/=302 mA/mm. This structure offers the promise of high-voltage applications at high frequencies on InP.<
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