SiC/Si heterojunction VDMOS breaking silicon limit by breakdown point transfer technology

Abstract

An innovative semiconductor power vertical double-diffused MOSFET (VDMOS) is proposed for the first time with the SiC/Si heterojunction at the P-base and N-drift region (called for SiC/Si VDMOS), which improves the trade-off between the breakdown voltage ( BV ) and specific on-resistance ( R on,sp ). The `soft' Si material has been combined with the `hard' SiC material to play their own advantages for SiC/Si VDMOS. The Si has been formed above the 6H-SiC substrate to make up the channel and source electrode, and the 6H-SiC is underneath the P-base to form the SiC/Si heterojunction. The novel terminal technology of breakdown point transfer has been advanced for the first time and applied to SiC/Si VDMOS, which transfers the breakdown point of SiC/Si VDMOS and improve the BV compared with Si VDMOS. The simulated results have been shown that the optimised BV of proposed SiC/Si VDMOS is increased from 226 to 578 V compared with the conventional Si VDMOS with the same drift region length, which is because the breakdown point is transferred from the higher electric field area with the maximum curvature radius to the low electric field area. The simulated R on,sp of SiC/Si VDMOS is 17.4 mΩ·cm 2 with the BV of 578 V, which is lower than that of 41.01 mΩ·cm 2 with the BV of 226V in Si VDMOS. The silicon limit relationship has been broken for SiC/Si VDMOS.