Improvement of GaAs Metal-Semiconductor Field-Effect Transistors Characteristics on SiO2 Back-Coated Si Substrate by Metalorganic Chemical Vapor Deposition

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Abstract
We have shown that the use of SiO2 back-coated Si substrate is effective in obtaining a low background electron concentration in an undoped GaAs layer grown on Si, particularly at high temperature, by MOCVD. Higher growth temperature improves the crystallinity of the GaAs layer grown on Si and helps to suppress the sidegating effect of GaAs MESFET's fabricated on Si. A low background electron concentration in the undoped GaAs layer is required for good pinch-off of the MESFET's. By using SiO2 back-coated Si substrate, the undoped GaAs with an electron concentration of as low as 1×1015 cm-3 could be grown even at 750°C. The maximum transconductance of 160 mS/mm, good pinch-off and suppressed sidegating were achieved for the 2.5 µm gate length MESFET on SiO2 back-coated Si.