Audio-frequency glow discharge for plasma chemical vapor deposition from organic compounds of the carbon family

Abstract

An audio-frequency (af) (10–100 kHz) glow discharge has been used for plasma chemical vapor deposition of thin films from organic compounds of the carbon family. It has been realized employing a recently designed reactor, equipped with three electrodes—a small electrode on which films are deposited, and two main electrodes sustaining a glow discharge. The small electrode and one main electrode are connected by a variable capacitance C. It has been found that small changes of C can cause a drastic change in the electronic properties of deposited films. This effect, attributed to a transition between the amorphous insulator (a-I) and amorphous semiconductor (a-S), is discussed for hydrogenated carbon–silicon, carbon–germanium, carbon–tin, and carbon–lead films produced from adequate organometallic compounds. To better understand the deposition process in the reactor, the electrical characteristics of model argon plasma have been investigated by means of a Langmuir single probe movable in the space between t...