In-situ Electron-spin-resonance Observation of Creation and Annihilation of Surface Dangling Bonds

Abstract

Technique of a newly developed in-situ electron-spin-resonance (ESR) is introduced for understandings of micro-scopic mechanism of dangling-bond creation and annihilation in Si oxidation processes as well as in deposition and plasma treatments of hydrogenated amorphous silicon (a-Si: H). 1) Dynamic changes of surface states during the Si oxi-dation process have been observed; ad-atom dangling bonds in Si(111)77 structure, termination of ad-atom dangling bonds due to oxidation, and creation of interface dangling bonds between Si and SiO2 thus formed. 2) Dynamic changes of the Si dangling-bond signal intensity were observed during and after the a-Si: H deposition, which confirms the exis-tence of a subsurface region with a quite high spin density (10 13 cm 2) only during the deposition process. 3) During hy-drogen plasma treatments on a-Si: H hydrogen atoms create dangling bonds, rather than terminate them. These dangling bonds are not confined to the film surface but are spatially distributing to the deeper layers from the top-surface (around 100 nm), whose depth decreases with the increase in the treatment temperature.