# Optimization and Simulation on Gas Flow and Temperature Fields on the Homoepitaxial Growth of N-Doped 4H-SiC Wafers

## TL;DR

This paper studies how to improve nitrogen doping uniformity in 4H-SiC wafers by optimizing CVD growth parameters and simulating gas flow and temperature fields.

## Contribution

The study provides a systematic analysis and simulation of CVD parameters to achieve uniform N doping in large-size 4H-SiC wafers.

## Key findings

- Optimized CVD parameters lead to a stable flow field and uniform temperature distribution.
- Site-competition epitaxy and on-track depletion are linked to doping profile uniformity.
- A W-shaped doping profile is observed and analyzed under various growth conditions.

## Abstract

The uniformity of nitrogen (N) doping concentration in 4H-SiC epitaxial wafers is a critical determinant of electrical consistency and device reliability. In this study, key chemical vapor deposition (CVD) growth parameters, including the C/Si ratio, H2 carrier gas flow rate, flow split ratio, and growth temperature, were systematically adjusted to investigate their effects on the N doping concentration and uniformity of 6-inch 4H-SiC homoepitaxial layers. The relationships between these parameters and characteristic phenomena such as site-competition epitaxy, along-track depletion of carbon source, and the distinct “W-shaped” doping profile were comprehensively analyzed. Furthermore, simulations of the flow and temperature fields within the reaction chamber and across the SiC epitaxial wafer revealed that under optimized conditions a stable parallel flow field forms above the wafer, accompanied by a uniform temperature distribution, thereby creating an ideal environment for homogeneous N doping. This work provides both theoretical insight and practical guidance for enhancing doping uniformity in large-size SiC epitaxial wafers.