Jet Impingement Configuration Research Articles

2D modelling of a non-confined circular impinging jet reactor; Si chemical vapour deposition

The 2D modelling of a chemical vapour deposition reactor with a non-confined impinging jet configuration has been undertaken. The deposition rate of silicon from an initial gas mixture composed of SiH 4-H 2 has been numerically investigated as a function of various parameters such as substrate temperature, total pressure, gas flow rate, distance between nozzle exit and substrate, and direction of the jet with respect to the gravity field to determine the role of natural convection. Both gas-phase and surface reactions were considered in the 2D model which takes into account variable physical properties. It is concluded that intermediate species generate specific thickness profiles. In addition, the kinetic control case is compared to the upper limit case of deposition rate where the gas phase is supposed to be in chemical equilibrium.

A mathematical model for a plasma-assisted downstream etching reactor

A mathematical model was developed for a plasma-assisted downstream etching reactor of the impinging jet configuration. Finite-element methods were employed to solve for the two-dimensional fluid velocity, temperature, and active species concentration distributions. Etching of a polymer (e.g., photoresist) using pure oxygen was analyzed with emphasis on the effect of reactor design and operating conditions on etching rate and uniformity. For a given flow rate, an optimum value of pressure was identified which maximized the etching rate. The etching rate increased monotonically with power, but decreased exponentially with distance between the plasma and the wafer. Under the conditions examined, the etching rate was found to be highest at the wafer center. Local loading was observed around the periphery of the wafer at high wafer temperature. The etching uniformity was found to depend on the gas-flow distribution. A new reactor design was proposed to achieve efficient gas dissociation in the plasma, rapid transport of the dissociated gas to the etching chamber, and nearly uniform flow distribution over the wafer. The new design resulted in improvement in both etching rate and uniformity.

Navier-Stokes Computations of Turbulent Compressible Two-Dimensional Impinging Jet Flowfields

Planar mass-averaged compressible Navier-Stokes and energy equations in stream function/vorticity form are solved in conjunction with a two-equation (fc-e) turbulence model for impinging jet configurations relevant to VTOL aircraft design. The physical domain of the flow is mapped conformally into a rectangular computational region. An augmented central-difference scheme is used to preserve the diagonal dominance character of the difference equations at high Reynolds numbers. The resulting difference equations are solved by successive point relaxation. Excellent agreement with the experimental data is obtained for the airframe undersurface pressure, ground-plane pressure, and the centerline velocity decay along the jet axis. Computed turbulent kinetic energy along the jet axis, however, has a larger overshoot near the ground plane than indicated by the experimental data.