Noise Spectroscopy for the Investigation and Characterization of Ultra-Thin Gate Dielectrics

Purdue University, West Lafayette IN

Investigators

Abstract

The goal of our research is to develop a new and highly sensitive technique for the characterization and investigation of stress-induced breakdown in the advanced, ultra-thin gate dielectrics which constitute one of the key components for next state-of-the-art and next generation VLSI technology. Our technique of Noise Spectroscopy is based on the realization that dielectric breakdown must involve the breakage and rearrangement of atomic bonds arising from the impact of energetic carriers (electrons or holes) which invariably leads to the formation of CARRIER TRAP STATES. EXCESS CURRENT NOISE in the tunneling, leakage current through gate dielectrics represents an extremely sensitive probe of both the presence and the nature of these TRAPS which serve as stepping stones in the tunneling process and therefore the detailed and systematic investigation of excess noise via Noise Spectroscopy has the potential of providing direct information on the QUALITY OF DIELECTRIC FILMS immediately after growth as well as the PATHWAY TO DIELECTRIC BREAKDOWN. The potential impact of this research in the shorter term is the development of a more sensitive and informative technique to ascertain the quality and robustness of ultra thin gate dielectrics which will be useful to the silicon VLSI industry complementary to conventional charge to breakdown and CV techniques. In the longer term, when a clear understanding of the physical mechanism of dielectric breakdown is achieved it should lead to the ability to design and manufacture better and more robust gate dielectrics e.g. via addition of trace impurities to pin atomic motion and reduce trap formation. In terms of education, we intend to involve three graduate students, one for the Noise Spectroscopy technique and the others for dielectric growth. Both aspects will involve state-of-the-art methods in the respective areas. In addition we plan to foster industrial ties to the fullest extent.