The effect of atomic composition on the rate of plasma chemical etching of silicon nitride in
power transistors based on an AlGaN / GaN heterojunction is studied. It is shown how the
subsequent process of its plasma-chemical etching depends on the configuration of the
incorporation of hydrogen impurity atoms into the molecular structure of the silicon nitride
deposited in the plasma. The dependence of the etching rate on the parameters of the process
(the working pressure in the chamber, the power of the plasma generator, the flow of working
gases, the deposition temperature) is investigated. It was shown that the etching rate of the
HxSirNzHy film does not depend directly on the hydrogen content, but significantly depends
on the ratio of [Si-H] / [N-H] bonds. The etching rate of HxSirNzHy in a high-density plasma
at low powers is much less dependent on the configuration of hydrogen bonds than the
etching rate of this dielectric in a buffer etchant.