High quality and very thin active layer formation for ion implanted GaAs mesfets

High quality and very thin active layer formation for Si ion implanted GaAs MESFETs is investigated by capacitance-voltage and photoluminescence (PL) measurements. In lower temperature region, carrier concentration increases as the PL peak intensity at wavelength of about 1.3 μm decreases, which is thought to be associated with a Ga-vacancy (V_Ga) -related deep acceptor. In the higher temperature region, the decrease in carrier concentration corresponds to the Si_As acceptor generation. Very thin active layers with few acceptors due to V_Ga and Si_As, are applied to MESFETs with Au/WSiN gates. The MESFETs with 0.35-μm gate-length exhibit a maximum transconductance of 660 mS/mm and a cutoff frequency of 76 GHz, which are better than the performance of GaAs HEMTs with the same gate-length.