A Mathematical Model of the Fluid Mechanics and Gas‐Phase Chemistry in a Rotating Disk Chemical Vapor Deposition Reactor

Abstract

We describe a mathematical model of the coupled fluid mechanics and gas‐phase chemical kinetics in a rotating disk chemical vapor deposition reactor. The analysis is for the flow between an infinite radius, heated nonporous rotating disk and a parallel infinite radius porous surface through which reactive fluid is injected normal to the disk. The analysis extends the usual von Karman transformation to allow specification of the normal velocity at the porous disk, and reduces to a stagnation point flow in the limit of zero rotating rate. The deposition of silicon from silane is used as an example system. A new reaction mechanism and set of rate constants are given for the thermal decomposition of silane. We present an RRKM analysis of several of the unimolecular reactions in the mechanism. Calculated velocity and temperature profiles, chemical species density profiles, and deposition rates as functions of susceptor temperature, spin rate, and inlet flow velocity are presented.

Thermochemistry and Kinetics of Silicon Hydride Cluster Formation during Thermal Decomposition of Silane

“…In particular, Breiland, Coltrin, Ho, and co-workers at Sandia National Laboratories have made extensive comparisons of mathematical models and experimental measurements of silicon growth rates and reactive species concentration profiles. [1][2][3][4][5][6][7] There is also a substantial body of work on the kinetics of gas-phase reactions of small silicon hydrides. [8][9][10][11][12][13][14][15][16][17][18][19][20][21][22][23][24][25][26] On the basis of this body of research, models of thermal CVD of silicon from silane can now predict film growth rates and precursor utilization with reasonable accuracy and reliability, at least under conditions where particle formation is negligible.…”

Numerical Methods for Reacting Gas Flow Simulations

“…The 26 gas phase reactions between the 17 gas phase species in this chemistry model, taken from [3,7], are listed in Table 1. The reaction terms in Eq.…”

Numerical Modelling of CVD Processes and Equipment

“…For this system quite a clear understanding has been developed, and the most important species and reactions have been identified. [2,3,41. Similar studies, but with a smaller number of species have been performed also for WF6 [23], TEOS chemistry [6], silicon nitride [7], and silicon carbide deposition [21].…”

“…Equipment simulation of reactors for undoped polysilicon deposition from SiH4 gas appears to be the most widely studied [2, 3,41, and the models have been validated through comparison with experiments [5]. CVD of silicon dioxide [6], silicon nitride [7], MOCVD for GaAs deposition [8], and tungsten CVD 19, 10, 11, 121, have also been studied through simulation, although the chemical reaction models used have been less thoroughly investigated.…”