The optimization of plasma-enhanced chemical-vapour-deposited amorphous SiN(x)H(y) (a-SiN(x)H(y)) layers for thin film diode (TFD) application in active matrix liquid crystal displays is discussed. The layers are deposited from SiH4-N2 and SiH4-N2-H-2 gas mixtures and the flow dependence of the deposition rate is an important reactor characteristic. In comparison with undiluted growth the flow dependence of the deposition rate for hydrogen-diluted growth is relatively weak over a wide flow range. Also, in the case of hydrogen dilution the achieved uniformity of both the a-SiN(x)H(y) layer thickness and the a-SiN(x)H(y) optical gap is higher. The uniformity of the a-SiN(x)H(y) layer properties correlates with the uniformity of the TFD I - V characteristic, and for a-SiN(x)H(y) with an optical gap of 2.10 eV the uniformity of the I - V characteristic improves markedly with hydrogen dilution. Finally, the possibility of obtaining a selected a-SiN(x)H(y) optical gap for several compositions is discussed and a correlation between the hydrogen content of the a-SiN(x)H(y) and the TFD stability is noted.