GaAs MMIC thermal analysis for epoxy-mount compared with AuSn-mount

Abstract

The effect of attachment for chip-mounting upon the thermal resistance of GaAs power FET modules has been experimentally investigated. The thermal resistance was evaluated by electrical method, which is related to the temperature dependence of Schottky-barrier in the GaAs MESFETs. The thermal resistance of low-cost epoxy-mounted modules was found to be almost the same as that of AuSn-mounted ones for a chip-thickness of 250 /spl mu/m. Applicable expression has also been presented for optimizing thermal design of power MMICs, suggesting that the optimum chip thickness depends on the thermal conductivity of attachment material.