Improving breakdown voltage of SiC/Si heterojunction with graded structure by rapid thermal CVD technology

A novel graded process has been developed to improve the characteristics of SiC/Si heterojunction diode (HJD) by rapid thermal chemical vapor deposition (RTCVD). The graded process was obtained by varying the flow of C/sub 3/H/sub 8/ gas from 0-10 sccm with a ramp rate of 2 sccm/min. The developed SiC/Si heterojunction diodes exhibit good rectifying properties. At forward bias, the built-in voltage of 0.63 V and excellent ideality factor n=1.28 were obtained by C-V and I-V measurements, respectively. For reverse bias, the breakdown voltage more than 16 V with low leakage current density is 3.74/spl times/10/sup -4/ A/cm/sup 2/ at 16.2 V reverse bias. Additionally, the SEM and TEM cross section have been employed to evidence that the graded method has a better SiC/Si interface than the conventional carbonization process.