A novel silicon carbide(SiC)on silicon(Si)heterojunction lateral double-diffused metal-oxide semiconductor field-effect transistor with p-type buried layer(PBL Si/SiC LDMOS)is proposed in this paper for the first time.The heterojunc-tion has breakdown point transfer(BPT)characteristics,and the BPT terminal technology is used to increase the breakdown voltage(BV)of Si/SiC LDMOS with the deep drain region.In order to further optimize the surface lateral electric field distribution of Si/SiC LDMOS with the deep drain region,the p-type buried layer is introduced in PBL Si/SiC LDMOS.The vertical electric field is optimized by Si/SiC heterojunction and the surface lateral electric field is optimized by the p-type buried layer,which greatly improves the BV of device and alleviates the relationship between BV and specific on-resistance(Ron,sp).Through TCAD simulation,when the drift region length is 20 μm,the BV is significantly improved from 249 V for the conventional Si LDMOS to 440 V for PBL Si/SiC LDMOS,increased by 77％;And the BV is improved from 384 V for Si/SiC LDMOS with the deep drain region to 440 V for the proposed structure,increased by 15％.The figure-of-merit(FOM)of the Si/SiC LDMOS with the deep drain region and PBL Si/SiC LDMOS are 4.26 MW/cm2 and 6.37 MW/cm2,respectively.For the PBL Si/SiC LDMOS with the drift length of 20 μm,the maximum FOM is 6.86 MW/cm2.The PBL Si/SiC LDMOS breaks conventional silicon limit.