去除外延用掺Fe磷化铟晶片表面Si残留的清洗方法

Cleaning Method for Removing Si Residue on the Surface of Fe-doped Indium Phosphide Wafers for Epitaxy

使用常规的清洗工艺清洗后磷化铟衬底晶片在外延后会出现迁移率低的表现,对缺陷的外延晶片进行分析,发现衬底与外延层界面Si元素的含量较大。针对该问题提出了优化的清洗工艺,对常规的SC1清洗工艺进行浓度优化并使用两步清洗,以及在过程中增加柠檬酸溶液清洗来解决Si元素的残留。对优化工艺前后晶片的氧化层厚度、晶片表面颗粒残留、晶片表面粗糙度、晶片的XRD和PL谱图进行了对比分析,并对优化清洗工艺清洗的晶片表面和外延界面Si元素含量进行了测试,结果表明优化清洗工艺能明显提高晶片表面洁净度并降低晶片表面Si元素的残留,最终解决由于Si元素含量较高造成的外延迁移率低的问题。

The INP substrate wafer after being cleaned by conventional cleaning process will have a defect of low mobility after epitaxy.The analysis of the epitaxy wafer with defect shows that the Si element content at the interface between substrate and epitaxy layer is large.To solve this problem,an optimized cleaning process was proposed.The concentration of conventional SC1 cleaning process was optimized and the optimized cleaning solution was used for two-step cleaning,and citric acid solution was added to the process to solve the residual Si element.The thickness of oxide layer,particle residue on the wafer surface,surface roughness of the wafer,XRD and PL spectra of the wafer before and after the optimization process were compared and analyzed,and the content of Si element on the wafer surface and the epitaxial interface were measured.The results show that the optimized cleaning process can obviously improve the cleanliness of the wafer surface and reduce the Si element residue on the wafer surface,and finally solve the purpose of low epitaxial mobility caused by high Si element content.