Recognition of D defects in silicon single crystals by preferential etching and effect on gate oxide integrity

Abstract

A method for revealing point defects in silicon single crystals has been investigated. D or A defects could be revealed by a Preferential etching technique using Secco's etchant. Wedge-shaped flow patterns and etch pits were recognised in the D and A regions, respectively. The flow patterns were so characteristic that the D region could be distinguished very easily.

Microdefects in Nitrogen Doped FZ Silicon Revealed by Li⁺ Drifting

“…The effect of N doping on the apparently complete suppression of the D defect region was first reported by Abe and Harada using X-ray topography of Cu decorated FZ Si [17]. Yamagishi et al saw the same result using the Secco etch technique [4]. This effect was also seen with the elimination of COPS and FPDs and an increase in GO1 [4,.…”

“…Yamagishi et al saw the same result using the Secco etch technique [4]. This effect was also seen with the elimination of COPS and FPDs and an increase in GO1 [4,. In 0-free Si, Ni pairs having CU, symmetry are the dominant defect [18].…”

“…We believe the precipitation sites are vacancies, or D defects. Since it has been reported that N doped Si is fiee of D defects, it was of some interest to verifjl this assumption with the Li' drifting process and to compare its sensitivity to that of the commonly promoted Si crystal characterization techniques discussed above [4,9,11,17].…”

“…Yamagishi et al have demonstrated that point defects can be revealed in Si wafers by using a Secco etch and examining the surface morphology of the resultant patterns with optical microscopy [4,5]. The surface morphology of the A defect region is striated while the D defect region shows flow-like patterns called flow pattern defects (FPD).…”

Microstructural Analysis of Epitaxial Layer Defects in Si Wafer

“…Thus, their structural characterizations have been the subject of intense theoretical and experimental investigations. [3][4][5] Normally, when the wafer growth rate is about 1.0 mm/ mim or higher, grown-in defects called crystal originated particles (COPs), of about 0.1 µm in size and 10 6 /cm 3 in density, are formed. 6) Nakai et al 7) has reported that when the growth rate is about 0.4 mm/min or lower, dislocation clusters of 10 6 /cm 3 density are observed in CZ Si wafers.…”