Low-temperature plasma deposition of passivating layers with low hydrogen content for optoelectronic devices

We have deposited silicon nitride (SiN) and Silicon oxynitride (SiON) thin films at low substrate temperatures (T8) using 2.45 GHz electron cyclotron resonance plasma enhanced chemical vapour deposition (ECRPECVD) and 13.56 MHz magnetron plasma enhanced chemical vapour deposition (MPECVD) techniques. Either a mixture of SiH4, N20 and Ar or SiH4, N2 and Ar was taken an precursor game. In the ECRPECVD the deposition rate varied between 20 to 7 nm/min with the ratio of flow rates of N2O (N2) to SiH4. The amount of incorporated hydrogen which was determined from nuclear reaction 15.N(1.H,alpha, delta)(exp 12) C analysis (NRA) varied similarly with gas flow rates ratio. By varying this ratio high-quality films with hydrogen content down to 11 at.per cent could be deposited at T5 = 150 deg C. In the MPECVD the typical deposition rates were on the order of 350 mn/min at 25 'C, substantially higher than has been reported for low-temperature deposition. The hydrogen content was found to be betw een 3-7 at. per cent, much lower than is typical for room-temperature PECVD films.