Selectively oxidized GaAs MESFETs transferred to a Si substrate

A novel method to electrically isolate grafted integrated GaAs devices from a conductive host substrate is demonstrated. An array of GaAs MESFETs is fabricated on a GaAs substrate and transferred to a Si substrate using a substrate removal process. The MESFETs contain a buried oxide layer under the channel region of each transistor that is formed by the thermal oxidation of AlAs. The purpose of this oxide layer is to provide electrical isolation from the conductive host substrate. Electrical evaluations are performed that show the transistors are fully functional after the oxidation and transfer processes and that the buried oxide does provide electrical isolation from the conductive host substrate.