OES diagnostics of NF₃/Xe plasma for deep structures in LiNbO₃

Abstract

In this work, in situ non-perturbing method of optical emission spectroscopy is used to examine the features of the emission spectra of NF3/Xe plasma, which can be used for the process of continuous plasma-chemical etching of lithium niobate. To understand the physicochemical processes occurring in plasma, the influence of high-frequency power, pressure in the chamber, bias voltage and substrate temperature on the emission intensities of the F, N, Xe lines was studied. It was determined that increasing the bias voltage from -300 to -50 V and the temperature from 50 to 300°C doesn’t change the relative intensities of the analysed spectral lines, while increasing the high-frequency power from 500 to 750W and decreasing the pressure from 1.95 to 0.95Pa increase the intensities of the F, N, Xe lines.