INDICATION OF LATERAL NONUNIFORMITY OF EFFECTIVE OXIDE CHARGES IN HIGH-k GATE DIELECTRICS BY TERMAN's METHOD

摘要

The Terman's method for interface trap density (DO extraction is utilized to examine the existence of lateral non-uniformity (LNU) of effective oxide charges in MOS(n) capacitors. The two parallel capacitors model is constructed to simulate the LNU charges, and it was shown that negative effective Da appears when LNU charges exist in gate oxide. This technique was used to detect the extent of the non-uniformity of effective oxide charge distribution in Al_2O_3 high-k gate dielectrics prepared by nitric acid (HNO_3) oxidation of ultra-thin Al films deposited on semiconductor substrates. It was found that LNU charges exist in Al_2O_3 experimentally and this observation is in agreement with the simulation result.