Effect of Oxygen Dose Variation on the Simox Microstructure

Abstract

AbstractThe effect of oxygen dose variation on the SIMOX SOI structure has been investigated extensively in this work. Keeping other implantation parameters constant, the dose has been varied from 0.2x1018cm–2 to 1.4xl018cm–2. Our studies show that a critical dose exists for a particular implant energy, below which a continuous buried oxide layer does not form. Further, the SiO2 precipitates enhance the pinning of defects in the as-implanted state which subsequently grow into threading dislocations. A dose window exists, where the dislocation density is a minimum.The oxygen depth distribution in the as-implanted and annealed state has been studied using SIMS. HRXRD measurements have been performed to reveal the strain state as a function of dose variation. The defect microstructure has been investigated using PTEM, XTEM and Secco Etching. AFM studies show the quality of the Si surface and Si/BOX (Buried OXide) interface roughness. This work gives us a fundamental understanding of the evolution of the defect microstructure and strain from the as-implanted to the annealed state using independent implantation parameter control.