Effect of Flip-Chip Die-Attach on the Thermal Behavior of Power GaAs Diodes

Abstract:
Gallium arsenide (GaAs) has a thermal conductivity three times lower than silicon (Si). This makes thermal management of GaAs power devices an important aspect when working with such devices. Flipchipping can shorten the thermal path and lower the thermal resistance. The thermal behavior GaAs pin-diodes rated for 1200 V and 20 A was evaluated in finite element method (FEM) simulations and experimentally. The experimental measurements show that a standard non-flipped device reaches a junction temperature (Tj) of up to 117deg C while the flipped variant heats up to 104deg C under the same conditions. The simulation results show the same tendency and are in good accordance with the nonflipped devices, jet yield a much lower temperature for the flipped devices as observed in reality.