Behavior of Thermally Induced Defects in Heavily Boron-Doped Silicon Crystals

Abstract

The effect of the first-step heat treatment temperature on the bulk microdefect (BMD) and oxidation-induced stacking fault (OiSF) formation in two kinds of heavily boron-doped silicon wafers, with and without an OiSF ring area, were investigated by comparing it with that in lightly boron-doped wafers. The BMD density was observed to be higher in the heavily doped silicon than in the lightly doped one at the same oxygen concentration. Unlike in the lightly doron-doped silicon, in the heavily boron-doped silicon, OiSFs were formed over the entire wafer surface regardless of the OiSF ring position when the first-step heat treatment was carried out at 900°C.

Elimination of strength degrading effects caused by surface microdefect: A prevention achieved by silicon nanotexturing to avoid catastrophic brittle fracture

“…The hard mask of SiO 2 was removed by buffer oxide etching (BOE), which also removed residues from the anti-acid protection tape, to obtain the most immaculate samples possible for the nanotexturing process. Electroless metal deposition etching was performed using 4.6 M HF and 0.02 M AgNO 3 that produced silicon nanotextures 26 on the samples, except for the V-notch, which was covered with polymer. The residual pattern formed as Ag dendrites were removed with an aqueous solution of 70% concentrated nitric acid (HNO 3 ) (refer to the supplementary material for the complete process, Fig.…”

“…Unavoidable large particles in the incoming slurry and agglomerated slurry on the polishing pad are the most likely causes of micro-scratches generated during the CMP process. This process can be controlled to an extent through process optimization, but optimization cannot effectively eliminate the presence of microdefects 26 .…”