GaAs MESFETs fabricated on Si substrates using a SrTiO3 buffer layer

Heteroepitaxial growth of GaAs on an Si substrate has been achieved through the use of crystalline SrTiO3 (STO) and amorphous SiO2 buffer layers. The buffer layers serve to accommodate some of the lattice mismatch between the substrate and the GaAs epilayers. Field-effect transistors fabricated in the GaAs epilayers show performance comparable to similar devices fabricated on GaAs substrates. The mobility in the GaAs/STO/Si sample is 2524 cm(2)/Vs compared to a GaAs/GaAs sample with mobility of 2682 cm(2)/Vs. A 0.7 mum gate length device has I-d max of 367 mA/mm and G(m max) of 223 mS/mm. These devices also have good RF performance with f(max) of 14.5 GHz and class AB power density of 90 mW/mm with an associated power-added efficiency of 38% at 1.9 GHz. This RF performance is within experimental error of similar devices fabricated on GaAs substrates. Preliminary reliability results show that after 800 h at 200 degreesC, the GaAs/STO/Si sample showed 1.2% degradation in drain current.