Abstract
Leakage currents through MIS (Metal Insulator Semiconductor) structures with several ultra-thin (14-30 angstroms) insulators (silicon dioxide, silicon oxynitride, and silicon nitride) have been investigated. The leakage currents through both dioxide and oxynitride films sandwiched between n-type poly-Si gates and n-type substrates can be well fitted by the equation for the electron direct tunneling mechanism using the same effective mass and barrier height. This result indicates that incorporation of a minute amount of nitrogen atoms does not seriously affect the basic electrical properties of the oxide films. Leakage currents through ultra-thin nitride can be also fitted with the equation for the direct tunneling mechanism without assuming any extra conduction mechanisms such as hopping through defects.