8英寸SiC晶圆制备与外延应用

Preparation and Epitaxy Application of 8 Inch SiC Wafers

碳化硅(SiC)是制作高温、高频、大功率电子器件的理想电子材料之一,近20年来随着SiC材料加工技术的不断提升,其应用领域不断扩大。目前SiC芯片的制备仍然以6英寸(1英寸=25.4 mm)晶圆为主,但是行业龙头企业已经开始研发基于8英寸SiC晶圆的下一代器件和芯片。本研究联合国内SiC产业链上、下游龙头企业,推进8英寸SiC芯片国产研发,尤其是关键的晶圆制备和外延应用环节。本文采用扩径生长法制备了8英寸导电型4H-SiC衬底晶圆,其平均基平面位错(BPD)密度低至251 cm^(-2),平均螺位错(TSD)密度小于1 cm^(-2),实现了近“零TSD”和低BPD密度的8英寸导电型4H-SiC衬底晶圆的制备,可以满足生产需要。采用国产8英寸外延设备和开发工艺包,实现了速率为68.66μm/h的快速外延生长,厚度不均匀性为0.89%,掺杂不均匀性为2.05%,这两个指标已经达到了优良6英寸外延膜的水平,完全可以满足生产需要。与国外已发布的8英寸外延结果对比,厚度和掺杂均匀性均优于国外数据,而缺陷密度只有国外数据的1/4。本文设计和实施了多片重复性试验,验证了8英寸外延的稳定性。

Silicon carbide(SiC)is one of the superior materials used in the manufacture of electronic components designed to work at high temperatures,high frequencies and high-power.In the past two decades,the application of SiC materials has been expanding as a result of much improved production and processing techniques.Although most SiC chips are still mainly made from 6 inch(1 inch=25.4 mm)wafers,leading manufacturers have begun developing next-generation parts and chips based upon 8 inch SiC wafers.This study collaborates with leading enterprises in the upstream and downstream of the domestic silicon carbide industry chain in order to facilitate domestic production of 8 inch SiC chips,with the focus being wafer preparation and epitaxial growth.In this work,8 inch conductive 4H-SiC substrate wafer was prepared by diameter expansion growth,with low average base plane dislocation(BPD)density(251 cm^(-2))and virtually‘zero threading screw dislocation(TSD)’density(<1 cm^(-2))that meet the production requirements.Based on these 8 inch substrates,we achieve fast epitaxial growth(68.66μm/h)with domestically produced 8 inch epitaxy equipment and processing packages.The thickness uniformity of the resultant wafers is 0.89%and the doping uniformity is 2.05%.These parameters,as well as the defect density,are on par with those of high-quality 6-inch wafers,fully meeting production requirements.The 8 inch wafers prepared in this paper are better than those described in international publications in terms of thickness and doping uniformity.The defect density is only 1/4 of international data.In this paper,multi-wafer repetative text was designed and executed,to verify the stability of 8 inch epitaxy.