Non-electronic properties of semiconductors (atomic structure, diffusion)

Study of the mask shape effect on the spatial distribution of GaAs layer growth rate in MOCVD selective area epitaxy

A. E. Marichev, V. V. Shamakhov, A. E. Grishin, S. O. Slipchenko, N. A. Pikhtin

Ioffe Institute, 194021 St. Petersburg, Russia

Abstract: Within a numerical model of gas-phase diffusion, the influence of the shape (square, circle, rhomb) and size (from 2 to 10 $\mu$m) of masks on the spatial distribution of the GaAs layer growth rate in metal-organic chemical vapor deposition selective area epitaxy has been studied. It was found that the growth rate enhancement changes non-uniformly around the periphery of square-shaped mask windows: it is minimal at the center of the square’s side and increases towards the vertices, with the maximum difference reaching 2.4%. Reducing the growth rate enhancement difference for a square window can be achieved by using a rhomb-shaped mask. The use of masks with circular windows ensures a minimal difference in growth rate enhancement between the center and the edge with the growth rate uniform around the entire periphery. It is shown that the smallest difference in growth rate enhancement between the window center and the edge can be observed with minimum mask-window widths and is 0.328% for a circular window.

Received: 14.10.2025
Revised: 13.11.2025
Accepted: 14.11.2025

DOI: 10.61011/FTP.2025.08.62186.8457