Spin dependent tunneling spectroscopy in 1.2 nm dielectrics

Abstract

We demonstrate voltage controlled spin dependent tunneling in 1.2 nm effective oxide thickness silicon oxynitride films. Our observations introduce a simple method to link point defect structure and energy levels in a very direct way in materials of great technological importance. We obtain defect energy level resolution by exploiting the enormous difference between the capacitance of the very thin dielectric and the capacitance of the depletion layer of moderately doped silicon. The simplicity of the technique and the robust character of the response make it, at least potentially, of widespread utility in the understanding of defects important in solid state electronics. Since the specific defect observed is generated by high electric field stressing, an important device instability in present day integrated circuitry, the observations are of considerable importance for present day technology. Since the observations involve inherent high sensitivity and tunneling, and since the process can be turned on and off with the application of a narrow range of voltage, our results may also be relevant to the development of spin based quantum computing.