GaAs抛光表面损伤的RBS研究

本文以卢瑟福离子背散射技术（ＲＢＳ）检测了半绝缘ＧａＡｓ（１００）化学机械抛光表面的微损伤状况，并以α台阶仪测量了抛光表面的粗糙度。研究了以胶体ＳｉＯ２和ＮａＯＣｌ溶液的混合液对ＧａＡｓ进行化学机械抛光方法中主要工艺条件对表面质量的影响。把ＲＢＳ法同Ｘ射线双晶衍射法对表面损伤的测量结果进行了比较，二者对应得很好。通过逐层腐蚀与ＲＢＳ相结合测定了抛光过程造成的损伤层的厚度，发现如果抛光条件不适宜，获得的晶片表面尽管目视光洁度很好，也还有一定厚度的损伤层。ＲＢＳ法测得好的非掺半绝缘ＧａＡｓ（１００）（由ＬＥＣ法生长）抛光表面散射粒子最低产额低达３１％，这样的晶片用腐蚀法未发现有损伤层。

Studies on Surface Damage of Polished GaAs Wafers by RBS Technique

On the surface of semi insulator GaAs (100) chemo mechanically polished wafers, the lattice damage and micro roughness were respectively determined by Rutherford back scattering (RBS) technique and Talystep instrument. The effects of main technical conditions of the chemo mechanically polishing method with the mixed solution of NaOCl and colloid SiO 2 on the surface quality were studied. As a comparison, the surface damage was also determined by the XDD technique, and the results show that it is as same as by the RBS technique. Thickness of damaged layer on the polished wafer surface was determined by layer by layer etching and the RBS technique. The results indicated that eye invisible damaged layer exits if the polishing conditions are not suitable and that no damaged layer is found if the polishing conditions are suitable. The minimum yield of scattered particles on the polishing surface of semi insulator GaAs wafer (LEC grown) measured by RBS technique is as low as 3.1%, and there is no damaged layer on the such surface.