Effect of Substrate Orientation on Interfacial and Bulk Character of Chemically Vapor Deposited Monocrystalline Silicon Carbide Thin Films

Abstract

The high breakdown electric field, saturated electron drift velocity, and melting (decomposition) point of SiC have given continual impetus to research concerned with the development of thin films having minimum concentrations of line and planar defects and electronic devices for severe environments. To this end, epitaxial growth via chemical vapor deposition of monocrystalline films of β‐SiC on Si (100) and 6H‐SiC {0001} substrates and 6H‐SiC on vicinal 6H‐SiC {0001} substrates have been conducted. High concentrations of stacking faults, microtwins, and inversion domain boundaries were produced in films grown directly on Si (100) as a result of a lattice parameter difference of ∼ 20% and the presence of single (or odd number) atomic steps on the substrate surface. Growth on Si (100) oriented 3° to 4° toward [011] completely eliminated the IDBs (but not the other defects) due to the preferential formation of double steps with dimerization axes on the upper terraces parallel to the step edges. Growth of β‐SiC films on 6H{0001} lowered the density of all defects but resulted in the formation of a new defect, namely, double positioning boundaries. The latter were eliminated by using 6H{0001} oriented 3° toward [1120]. The defect density in these last films, relative to those grown on on‐axis Si (100), was reduced substantially (to ∼105 cm/cm3). However, the resulting film was 6H‐SiC. Significant improvements in electrical properties of simple devices were obtained as the defect density was progressively decreased.