Current conduction in thermally grown thin SiO/sub 2/ films

Abstract

Hopewell Junction, N.Y. 12533The I-V characteristics of thin SiO, films with thicknesses ranging from 35 to 250A were studied using conventional Al gate MOS capacitors prepared on < 100> p type substrate as the test vehicle. Several measurement techniques including constant voltage, constant current and voltage pulse were used. Consistent results have been obtained. Time dependent currents are observed in the low field region, i.e. less than 8 MV/cm for oxides thicker than 5OA due to displacement currents and charge trapping. The slope of the Fowler-Nordheim plot is sensitive to the way the oxide field is estimated. For thicker oxides (greater than lOOA), the slope may have a value between 240-300 MV/cm depending on the estimated oxide field. For thinner oxides, the slope is smaller due to the enhancement in the direct tunneling effect.