Heteroepitaxial In0.1Ga0.9As metal‐semiconductor field‐effect transistors fabricated on GaAs and Si substrates

We present a comparison of device characteristics for In0.1 Ga0.9 As metal‐semiconductor field‐effect transistors (MESFETs) fabricated on GaAs and silicon substrates. The In0.1Ga0.9As layers are heteroepitaxially grown on GaAs and silicon substrates by metalorganic chemical vapor deposition. 0.5 μm gate devices fabricated on the GaAs substrate show a maximum extrinsic transconductance of 450 mS/mm and a current‐gain cutoff frequency ft of 55 GHz. Despite the large lattice mismatch, the In0.1 Ga0.9 As MESFETs fabricated on the silicon substrate show a comparable ft of 52 GHz with a lower gain.