Method of coating and etching

A method of chemical vapour deposition of a material on a substrate or etch of material from a substrate comprises using a short pulsed power signal to form a short pulsed plasma for enhancing the deposition or etch. The power signal is preferably a square,trapezoidal, near square or near trapezoidal wave. The plasma may be formed using helium, argon or nitrogen. The method may be performed at atmospheric or near atmospheric pressure or may alternatively be performed at sub-atmospheric pressure. The "on phase" pulse width of the short pulsed power signal is preferably less than or equal to 1 us. Also disclosed is equipment for chemical vapour deposition 10 of material on a substrate 32 or etch of material from a substrate comprising a holder 14 for a substrate 32, apparatus for forming a short pulsed plasma 36 near the holder and a power supply 38 configured to provide a pulsed power signal to form the short pulsed plasma