等离子体化学气相沉积法合成石英玻璃

用高频等离子体作为热源,采用化学气相沉积法合成了石英玻璃样品.实验分别使用02和空气作为等离子体电离气体和冷却保护气体,改变等离子体电离工作气体种类时,等离子体火焰长度和石英玻璃沉积温度变化较大,而灯具冷却保护气体的改变对等离子火焰长度和石英玻璃沉积温度的影响不大.当等离子体电离气体和灯具保护气体均为O2时,等离子体火焰长度为12cm,石英基体温度为1 300℃,当等离子体电离气体和灯具保护气体均为空气时,等离子体火焰长度可达24cm,石英基体温度升高到l 840℃,可确保气相沉积过程进行,合成的石英玻璃在波长190nm处光透过率达84%,羟基含量3.5×10-6,可达到全光谱透过的要求.

SYNTHESIS OF SILICA GLASS BY PLASMA CHEMICAL VAPOR DEPOSITION METHOD

Silica glass was synthesized by plasma chemical vapor deposition method, which uses inductively coupled plasma as theheat source. Air and oxygen were separately used as ionized gas and protecting gas. The influence of ionized gases on the length ofplasma flame and the temperature of substrate is more significant than that of the protecting gases. A length of 24 cm plasma flameand a deposition temperature of 1 300 ℃ were obtained when oxygen was used as both ionized gases and protecting gases, but in thecase of air, the length of plasma flame was 24 cm and the deposition temperature was 1 840 ℃. Both of the longer plasma flame andthe higher deposition temperature offered a good condition to deposit high quality silica glass. The silica glass has 84% transmittanceat a wavelength of 190 nm and 3.5 10-6 of the hydroxyl group, which is the glass of full-spectrum transmittance.