The effect of implantation temperature on defect production in SIMOX structures

Abstract

Electron paramagnetic resonance measurements have been made at X-band and room temperature on defects produced by implanting n-type (100) silicon wafers with 1.4*1018 cm-2 of 200 keV 16O+ ions at an implantation temperature, Ti, of 250, 350, 450 or 600 degrees C. The dose is not quite sufficient to form a continuous buried oxide layer in the as-implanted state. Four types of spectrum are observed and they are attributed to (i) E1' centres in oxide precipitates, (ii) D centres in damaged silicon, (iii) Pbo centres at the oxide/silicon interface of oxide precipitates embedded in regions of single-crystal silicon and (iv) the same in regions of amorphous or polycrystalline silicon. Increasing the implantation temperature from 250 to 600 degrees C leads, for the as-implanted state, to an increase in the E1' concentration from 1.5*1014 to 2.3*1014 cm-2 and a decrease in that of all the (Pbo+D) defects from 1.5*1015 to 1015 cm-2; the D centre concentration is estimated to decrease from about 5*1014 to 3*1014 cm-2. The concentration of all these defects starts to decrease above an anneal temperature of 400 degrees C and at higher temperatures the dominant defects become the Pbo centres. It also becomes clear that as Ti is raised the proportion of these centres in amorphous or polycrystalline silicon regions becomes less.