摘要
研究了研削工艺中磨轮目数对被减薄碳化硅(SiC)表面和欧姆接触的影响,并基于减薄工艺和激光退火工艺成功制备出170μm薄片SiC肖特基二极管。先后经过2 000目和7 000目磨轮减薄,衬底厚度从346μm降至170μm,晶圆减薄后表面粗糙度为5.4 nm。采用激光退火技术制备被减薄SiC样品背面欧姆接触,比接触电阻率达2.28×10^-5Ω·cm^2。在正向压降为1.5 V时,未减薄SiC肖特基二极管正向导通电流密度为488 A/cm^2,170μm薄片SiC肖特基二极管正向导通电流密度为638 A/cm^2,电流密度提升了30.7%,意味着通态损耗降低了30.7%,减薄后通态电阻降低了23.58%。同时,两种SiC肖特基二极管的反向特性、肖特基结电容、雪崩电流等电学特性几乎一致,说明减薄和激光退火工艺未对其他电学特性带来负面影响。
The influences of grinding wheel mesh on the thinned SiC surface and Ohmic contact in the grinding process were studied.Based on the thinning process and laser annealing process,the 170μm thin-wafer SiC Schottky diode was successfully fabricated.After successively thinned by grinding wheels of 2 000 mesh and 7 000 mesh,the thickness of the substrate was reduced from 346μm to 170μm.The surface roughness is 5.4 nm after the wafer-thinning process.Laser annealing technology was used to prepare the Ohmic contact on the backside of the thinned SiC sample.The specific contact resistivity reaches 2.28×10^-5Ω·cm^2.When the forward voltage is 1.5 V,the forward conduction current density of the un-thinned SiC Schottky diode is 488 A/cm^2,while that of the 170μm thinned SiC Schottky diode is 638 A/cm^2.The current density increases by 30.7%,which means that the on-state loss is reduced by 30.7%.The on-state resistance is reduced by 23.58% after wafer-thinning.At the same time,the electrical characteristics of the two kinds of the SiC Schottky diodes are almost the same,such as reverse characteristics,Schottky junction capacitance and avalanche current,indicating that the thinning and laser annealing processes have no negative effect on other electrical characteristics.
作者
刘敏
郑柳
何志
王文武
Liu Min;Zheng Liu;He Zhi;Wang Wenwu(Institute of Microelectronics,Chinese Academy of Sciences,Beijing 100029,China)
出处
《微纳电子技术》
北大核心
2020年第9期681-686,719,共7页
Micronanoelectronic Technology
基金
广东省重点领域研发计划资助项目(2019B010144001)。
