Abstract A novel n-SiC/p-Si heterojunction diode with high-temperature bi-directional N-shaped negative-differential-resistances (NRDs) was reported. At room temperature, the device possesses NDRs with peak-to-valley current ratios (PVCRs) of about 21 and 236 at forward and reverse biases, respectively. Under reverse biases, this device achieves an NDR with a PVCR of 40 at 200°C. In addition, it possesses obvious NDRs even up to 300°C. This high-temperature NDR characteristic provides this novel SiC/Si heterojunction diode a potential for high-temperature applications, such as high-temperature solid-state switches.