Effect of spray nozzle position on pad temperature distribution and wafer non-uniformity

Multi-technique characterisation of InAs-on-GaAs wafers with circular defect pattern

“…Its presence might be related to the release of defects from nonideal substrate or might result from the method of wafer surface polishing [44]. The heterogeneous stress distribution during mechanical planarization [45] or temperature distribution during this process [46] may also play a role. The circular shape of a pattern probably results from the lack of perfect flat parallelism of the wafer, which in turn affects the heat flows [47] or reflects difficulties in uniform heating of the wafer in the growth reactor [48].…”