Os RECTIFYING SCHOTTKY AND OHMIC JUNCTION AND W/WC/TiC OHMIC CONTACTS ON SiC

摘要

Metallic osmium on SiC (either β or α) forms a contact that remains firmly attached to the SiC surface and forms an effective barrier against diffusion from the conductive metal. On n-type SiC (12), Os (20) forms an abrupt Schottky rectifying junction having essentially unchanged operating characteristics to at least 1050 °C and Schottky diodes that remain operable to 1175 °C and a barrier height over 1.5 eV. On p-type SiC, Os forms an ohmic contact with specific contact resistance of ∫10?-4 ohm-cm2¿. Ohmic and rectifying contacts to a TiC layer (30) on a SiC substrate (12) are formed by depositing a WC layer (32) over the TiC layer (30), followed by a metallic W layer (34). Such contacts are stable to at least 1150 °C. Electrodes (38) connect to the contacts either directly or via a protective bonding layer (36) such as Pt or PtAu alloy.