Power device packaging technologies for extreme environments

Abstract

Silicon carbide is a wide-bandgap semiconductor capable of operation at temperatures in excess of 300 °C. However, high-temperature packaging to interface with the other elements of the electrical system is required. Die attach, wire bonding, and passivation materials and techniques have been demonstrated for use at 300 °C. Transient liquid phase bonding has been developed with Au:Sn/Au, yielding high die shear strength after 2000 h at 400 °C. Large diameter (250 μm) gold and platinum wire bonding was evaluated for top side electrical contact. Au wire was reliable after 2000 h at 300 °C with Ti/Ti:W/Au pads over passivation on the SiC. However, Au wire on Ti/Pt/Au and Pt wire on both Ti/TI:W/Au and Ti/Pt/Au exhibited passivation fracture with aging. Polyimide has been demonstrated for 2000 h at 300 °C in air as a high-voltage passivation layer. © 2007 IEEE.