Characterization of Double Stacking Faults Induced by Thermal Processing of Heavily N-Doped 4H-SiC Substrates

Abstract

Double stacking faults (3C lamellae) formed by thermal processing of heavily (~3x10 19 cm -3 n-type) doped 4H-SiC substrates, with or without lightly n-doped epilayers, are characterized by low temperature photoluminescence (PL), Raman scattering, secondary electron imaging (SEI), and electrostatic force microscopy (EFM). Electric fields are evident in the SEI and EFM images where the faults intersect the surface. Self-consistent simulations including spontaneous polarization explain several features observed in PL and Raman spectra.

Optical properties of as‐grown and process‐induced stacking faults in 4H‐SiC

“…It manifests only significantly for 3SSF (7,1) and, in this case, has been independently reported in the work of Ref. [41].…”

“…[41]. The common feature of these works is that, up to now, only 3C-SiC ribbons were concerned and that the change in optical SF signature was only a function of the well thickness.…”

“…[53], the upper spectrum is from Ref. [41]. In any case, the different series of phonon replicas identify the two transitions E g -(X) and E g + (X) which correspond with the two different possibilities for an electron -hole pair to recombine across a type-II QW.…”

Electrostatic Force Microscopy and Secondary Electron Imaging of Double Stacking Faults in Heavilyn-type 4H-SiC after Oxidation

“…However, the stacking fault energy of 4H-SiC is low (14.7 mJ/m 2 ) [1]. Double Shockley stacking faults are known to form spontaneously during high temperature thermal processing or oxidation of material with n-type doping above ~3x10 19 cm -3 [2][3][4][5][6][7]. They are believed to form on the (0001) <11-20> hexagonal slip system by dissociation of perfect dislocations into two partial dislocations, according to the reaction a/3 <2-1-10> → a/3 <1-100> + a/3 <10-10>.…”

“…Thin lamellae consisting of six bilayers in a 3C stacking sequence result. Electron transfer from the 4H matrix into the 3C layer, which acts like a quantum well (QW), may drive the transformation [4][5][6][7]. In previous work, we studied these faults using crosssectional transmission electron microscopy (TEM), X-ray topography, Raman scattering, low temperature photoluminescence (PL), and electrical measurements on Schottky barriers [2,6,7].…”