Modeling of a–Si:H deposition in a dc glow discharge reactor

Abstract

PECVD reactors are increasingly used for the manufacturing of electronic components. This paper presents a reactor model for the deposition of amorphous hydrogenated silicon in a dc glow discharge of Ar-SiH 4 The parallel-plate configuration is used in this study. Electron and positive ion densities have been calculated in a self-consistent way. A macroscopic description that is based on the Boltzmann equation with forwardscattering is used to calculate the ionization rate. The dissociation rate constant of SiH 4 requires knowledge about the electron energy distribution function. Maxwell and Druyvesteyn distributions are compared and the numerical results show that the deposition rate is lower for the Druyvesteyn distribution. The plasma chemistry model includes silane, silyl, silylene, disilane, hydrogen, and atomic hydrogen. The sensitivity of the deposition rate toward the branching ratios SiH 3 and SiH 2 as well as H 2 and H during silyl dissociation is examined. Further parameters that are considered in the sensitivity analysis include anode/cathode temperatures, pressure, applied voltage, gap distance, gap length, molar fraction of SiH 4 , and flow speed. This work offers insight into the effects of all design and control variables.

Silicon nitride (SiNx) plasma deposition on optical fiber sensors: coating symmetry perspective

“…It leads to a conclusion of non-uniformity of plasma created inside the reactor's chamber. It has been proven by numerical simulations [12] that the maximum amount of reactive products of SiH 4 dissociation is over the electrode and the concentration of them rapidly decreases with approaching electrode surface. This result explains the difference in kinetic of deposition process at different heights.…”

Silylenes

“…In the plasma, high-energy electrons are formed whose impact on silanes dissociates them into fragments, including SiH 2 and SiH 3 . Orlicki and coworkers have carried out an extensive modeling study of a glow-discharge reactor operated at ca 1 torr and 475 525 K 385 . It was predicted that for film growth at the cathode (where the growth rate is higher) the contribution from SiH 2 reaching the surface can be slightly higher than that of SiH 3 , or be significantly less, depending on the electron energy distribution function and on the branching ratio for formation of SiH 2 and SiH 3 from SiH 4 under electron impact.…”

Chemical Engineering Aspects of Advanced Ceramic Materials

“…This possibility has opened a rapidly growing new field of research and applications. Orlicki et al (1992) developed a model of a Si:H deposition in a dc glow discharge (Ar-SiH 4 ) reactor. The parallel-plate configuration is used in this study.…”