TiN plasma CVD coatings deposited by different excitation methods for the gas discharge

Abstract

Tin was deposited on high speed tool steel (1.3343) by use of different plasma chemical vapour deposition (PCVD) methods. R.f. PCVD without and with a d.c. substrate bias, d.c. PCVD, pulsed d.c. PCVD and downstream microwave plasma excitation were used. Whilst all methods but the microwave process gave hard (Knoop hardness less than or equal to 2500 HK) well-adhering coatings on flat substrates, differences can be observed in the thickness distribution on three-dimensional samples. Here the best coating uniformity can be achieved with the d.c. methods. When coating narrow holes the d.c. pulse process has the best throwing power. So of all the PCVD methods the d.c. pulsed PCVD process is the best suited for production of TiN coatings on three-dimensional parts.