Combined electron spin resonance and capacitance-voltage analysis of hydrogen-annealing induced positive charge in buried SiO2

Abstract

A novel charge sensing technique, based on monitoring donor defects in near-interfacial Si by electron spin resonance (ESR), has been applied to measure positive charge in buried oxide (BOX) layers of separation by implantation of oxygen material. This positive charge is introduced into the BOX layer by annealing in hydrogen in the temperature range 450–700 °C. Standard capacitance-voltage (C-V) analysis of the areal BOX-charge densities was used as a crucial test for this ESR-based method, yielding good agreement between the two techniques. Photoinjection of charges, optical excitation, and C-V and ESR etchback experiments have been performed on BOX layers subsequent to the hydrogen charging treatment leading to additional information on location, nature, and stability of the hydrogen-induced positive centers. The results show that these centers are very stable (not even affected by electron injection) and that they are located near the two Si/BOX interfaces (within a layer of ≤20 nm).