Numerical Simulation of Plasma Chemical Vapor Deposition from Silane: Effects of the Plasma-Substrate Distance and Hydrogen Dilution

Abstract

Rf plasma chemical vapor deposition from silane was numerically analyzed. When a substrate was moved away from the plasma, gas-phase polymerization increased the contribution of oligomer radicals to film deposition. In addition, the contribution of silylene radicals became lower compared with that of silyl radicals. As a result of the trade-off between these two effects, an optimal plasma-substrate distance, where a high-quality a-Si:H film was obtained, appeared. Dilution of feed silane with hydrogen effectively reduced gas-phase polymerization and enhanced the generation of hydrogen radicals that create silyl radicals selectively through a reaction with silane. Improvement of the film quality as a result of plasma-substrate separation and hydrogen dilution was thus explained by the change in the composition of film precursors.

Modeling of silicon nanoparticle formation in inductively coupled plasma using a modified collision frequency function

“…In this part, species density and electron temperature are determined. The second part [8] of the table describes the cluster growth by calculating the chemical reactions occurring among the species computed in the first part. In this second part of the table, nuclei, called first particles, are generated by cluster growth.…”

“…In this second part of the table, nuclei, called first particles, are generated by cluster growth. We define nuclei according to Kawase et al [8] as silicon hydrides (Si n H m ) that contain more than five silicon atoms. Information flow is expressed using an arrow for the electron heating module, and the plasma chemistry module is described using the Arrhenius equation and parameters listed in Table 1.…”

“…J. Perrin et al also presented basic data concerning the physics and chemistry of discharges of PECVD in a-Si:H film and described SiH 4 plasma chemistries during a-Si:H PECVD [7]. Motoaki Kawase completed a similar numerical analysis [8]. As indicated by these studies, research has focused on the relation of the plasma state to the composition of plasma for film deposition.…”

“…This model can numerically predict a set of spatially averaged fluid equations for ions, neutrons and radicals. Basic data for silane plasma consists of two types of data, suggested by S. H. Bae et al [13], who focused on the plasma state, Won-Gi Lee et al [16] and Motoaki Kawase et al [8], who focused on cluster growth. Data for the plasma parameter is modified by referring to the publication of R. K. Janev et al [17].…”

Optical emission spectroscopy of glow discharge plasma from SiH4−CH4 system

“…We now describe part of the decomposition process due to SiH 4 and CH 4 electron collisions [15][16][17]:…”