Measurement and Evaluation of Defects induced by Processing of Small Regions by means of Interface-Barrier-Controlled Electron Spin Resonance

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In order to know electronic levels as well as geometrical and electronic structures of defects or impurities in small regions of silicon which are induced by semiconductor processings, we have measured the interface-barrier-controlled electron spin resonance (ESR) by using electrode and have developed a new method of analyzing the temperature dependent ESR linewidth. In this study, the off-center substitutional nitrogen was introduced in silicon surface layer of 2000 A by ion implantation and subsequent laser annealing to obtain the samples.For the interface-barrier-controlled ESR, metal-oxide-semiconductor structure was formed to detect ESR changes by controlling the oxide-silicon interface-barrier. We clarified a few problems for this measurement; i.e., (1) leak current due to the large area (20 x 2 mm^2 ) of the electrode and (2) residual defects near the oxide-silicon interface. These must be solved to advance this mothod.For the newly developed method, we demonstrated that the electronic level of off-center substitutional nitrogen in silicon can be determined by analyzing the ESR linewidth obtained over a wide temperature region from 150 to 550 K. The temperature dependence observed above 330 K is interpreted in terms of motional broadening or shortening of the spin-lattice relaxation time via thermal excitation in the conduction band and trapping by the deep level. According to this analysis, we obtain an energy level of E_c - 0.33 eV and show that this mehtod is very useful for determination of defect levels as well as the structures.