Experimental demonstration of in situ surface and thickness profile measurements of thin film during deposition using a grating array based wavefront sensor
Nagendra Kumar, Biswajit Pathak, Rahul Kesarwani, Sumit Goswami, Alika Khare, Bosanta R. Boruah
Abstract
Here we introduce an in situ and non-intrusive surface and thickness profile monitoring scheme of thin-film growth during deposition. The scheme is implemented using a programmable grating array based zonal wavefront sensor integrated with a thin-film deposition unit. It provides both 2D surface and thickness profiles of any reflecting thin film during deposition without requiring the properties of the thin-film material. The proposed scheme comprises a mechanism to nullify the effect of vibrations which is normally built in with the vacuum pumps of thin-film deposition systems and is largely immune to the fluctuations in the probe beam intensity. The final thickness profile obtained is compared with independent off-line measurement and the two results are observed to be in agreement.