The IR properties in SOI wafers formed by oxygen implantation into silicon

Abstract

SOI (silicon-on-insulator) structures have been formed by high dose (1.8−2.0 × 10 18 O + cm −2) O + implantation into n-type (100) Si samples at 200–350 keV, after the different annealing methods. The SOI structures were evaluated by means of infrared absorption spectroscopy (IR) and electron paramagnetic resonance spectroscopy (EPR). After one-step high-temperature annealing, the buried SiO 2 layers in SOI wafers became amorphous. There are three major characteristic peaks in the IR spectra which are the same as those of the thermal SiO 2 film. The three absorption coefficients were calculated. A new nondestructive method to determine the thickness of a buried SiO 2 layer in the SOI wafers is suggested by using IR spectra without destruction of the wafers. After two-step annealing, the results of IR and EPR measurements proved that a crystalline buried SiO 2 layer in the SOI wafer was obtained. The vibration of the Si-Si band in this SOI wafer is much stronger than that in one-step annealed SOI wafers and the CVD SiO 2 and the thermal SiO 2 film. The absorption coefficient of the Si-Si band in this SOI wafer is about four times of that in the amorphous SiO 2 wafers.