Optimization of the SiC Powder Source Material for Improved Process Conditions During PVT Growth of SiC Boules.

Ellefsen Ellefsen,Arzig Arzig,Runde Runde,Steiner Steiner,Wellmann Wellmann

doi:10.3390/ma12193272

Abstract

We have studied the influence of different SiC powder size distributions and the sublimation behavior during physical vapor transport growth of SiC in a 75 mm and 100 mm crystal processing configuration. The evolution of the source material as well as of the crystal growth interface was carried out using in situ 3D X-ray computed tomography (75 mm crystals) and in situ 2D X-ray visualization (100 mm crystals). Beside the SiC powder size distribution, the source materials differed in the maximum packaging density and thermal properties. In this latter case of the highest packaging density, the in situ X-ray studies revealed an improved growth interface stability that enabled a much longer crystal growth process. During process time, the sublimation-recrystallization behavior showed a much smoother morphology change and slower materials consumption, as well as a much more stable shape of the growth interface than in the cases of the less dense SiC source. By adapting the size distribution of the SiC source material we achieved to significantly enhance stable growth conditions.

Highlights

In recent years, SiC has become the most important semiconductor material for the fabrication of power electronic devices as they are mandatory in electromotive and energy-saving applications.Crystal growth of SiC is generally carried out using the physical vapor transport (PVT) method
SiC powder source material is sublimed at elevated temperatures above 2000 ◦ C and crystallizes at a slightly colder seed
The evolution of the source material and its impact on the crystal growth process have been investigated in a number of studies that make use of 2D and 3D X-ray-based in situ visualization [9,10,11,12]

Summary

Introduction

Crystal growth of SiC is generally carried out using the physical vapor transport (PVT) method. For a review on the SiC bulk growth process, refer to [1]. A number of factors that impact the growth process, like stoichiometry, purity, polytype, size distribution and related packaging density, have been discussed [2,3,4,5,6,7,8]. The evolution of the source material and its impact on the crystal growth process have been investigated in a number of studies that make use of 2D and 3D X-ray-based in situ visualization [9,10,11,12]

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Conclusion