Deposition and characterization of hydrogenated amorphous silicon, microcrystalline silicon and silicon-based alloy thin films.

摘要

In this thesis, I primarily investigate the deposition and characterization of hydrogenated amorphous silicon (a-Si:H) film, microcrystalline silicon ({dollar}mu{dollar}c-Si) film and Si based alloy films (silicon carbon alloy and silicon germanium alloy) deposited by remote plasma-enhanced chemical-vapor deposition (remote PECVD) process and reactive magnetron sputtering (RMS) process.; By using RMS, I demonstrate that the hydrogen content, thereby the quality of a-Si:H films is not determined by any single deposition parameter, neither the substrate temperature, nor the hydrogen pressure. It is determined by the availability of hydrogen atoms at the film growing surface during deposition. Investigation of room temperature sputtered a-Si:H films leads to a new understanding of the role of deposition temperature in determining the film quality: not only to affect hydrogen in the film, but also to affect the relaxation of the film structure.; I demonstrate {dollar}mu{dollar}c-Si (or epitaxy Si) films can be deposited at low temperature ({dollar}<{dollar}300{dollar}spcirc{dollar}C) by remote PECVD and RMS processes. I show the remote PECVD {dollar}mu{dollar}c-Si films can be in-situ doped as both p- and n-type. These heavily doped {dollar}mu{dollar}c-Si films are applicable as the gate electrode in the MOS capacitor, in addition, as the contact layer, conventionally, in thin film devices. This result has a direct significance for the fabrication of integrated circuit (IC) using remote PECVD process.; I show for the first-time the identification of a new type {dollar}mu{dollar}c-Si film, which is intrinsic {dollar}mu{dollar}c-Si film deposited with lightly boron doped in the gas phase (B{dollar}sb2{dollar}H{dollar}sb6{dollar}/SiH{dollar}sb4{dollar} {dollar}sim{dollar} 10-{dollar}sp5{dollar}). This intrinsic {dollar}mu{dollar}c-Si film exhibits not only the comparable photovoltaic properties to the device-quality a-Si:H films, but also, most importantly, very high stability to light exposure: there is no detectable Steabler-Wronsky effect. I conduct the preliminary investigation of applying this intrinsic {dollar}mu{dollar}c-Si film in the PV devices and show a p-i-n device comprised of all {dollar}mu{dollar}c-Si layers: heavily doped p- and n- regions of {dollar}mu{dollar}c-Si, and i-regions of intrinsic {dollar}mu{dollar}c-Si films, display good rectification and strong photovoltaic effect.; I show that two types of Si based binary alloy, Si,C and Si,Ge films, both amorphous and crystalline, can be deposited by remote PECVD. I investigate the relation of the deposition conditions to the properties of these two binary alloy films.