反应离子刻蚀损伤对4H-SiC肖特基二极管性能的影响

Effect of Reactive Ion Etching Damages on the Performances of 4H-SiC Schottky Barrier Diodes

通过反应离子刻蚀（RIE）系统地研究了射频功率、压强和气体流量对4H-Si C刻蚀的影响,并进一步研究了刻蚀损伤对金属场板结构4H-Si C肖特基势垒二极管电学性能的影响。研究表明,刻蚀速率和Si C表面形貌都会受到RF功率、压强和刻蚀气体（SF6和O2）流量的影响。在高的RF功率下,观察到在Si C表面形成的刻蚀损伤（凹陷坑和锥形坑）。研究表明,这些刻蚀损伤的形成和Si C材料自身的缺陷有关,而且这些刻蚀损伤的存在会导致Si C肖特基二极管正反向I-V性能发生恶化。在刻蚀损伤严重的情况下,对比正反向I-V测试结果发现,在0～50 V的绝对电压范围内,正向电流甚至远小于反向电流。

By the reactive ion etching（ RIE）,the effects of the RF power,pressure and the gas flow on the 4H-Si C etching were studied systematically. The influences of the etching damage on the electrical properties of the Si C Schottky barrier diodes（ SBDs） with metal field plate structure were analyzed. The results show that the etch rate of the 4H-Si C as well as Si C surface morphology are related with process parameters,such as RF power,pressure and the flow of gas（ SF6 and O2）. Etching damages（ the cone-in-pits and pits） generated on the Si C surface at high RF power were observed. The research shows that the etching damages may be caused by the defects in Si C materiel itself. The degradations of both the reverse and forward I-V performances of Si C SBDs were ascribed to the cone-in-pits and pits. Moreover,the absolute value of forward current is even less than that of the reverse counterpart in the absolute value voltage range of 0- 50 V for Si C SBDs with the serions etching damages.