Preparation and Epitaxy Application of 8 Inch SiC Wafers
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(68.66 μm/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.
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