Properties of Gold Doped MOS Structures

Abstract

The theoretical capacitance‐voltage characteristics of gold‐doped metaloxide‐silicon structures have been calculated and compared with experiment for both the high and the low frequency cases. It is found that gold diffused from the back side causes a negative interface charge Q Au in addition to the usual positive Q ss . Evidence is presented to show that the gold responsible for Q Au is located in the silicon very near the oxide silicon interface. Gold diffused from the top side (through the oxide) results in a positive Q Au indicating that gold in the oxide near the interface is positively charged. Temperature‐bias tests showed that Q Au was stable under conditions which mobile alkali ions such as sodium drift rapidly. In addition, an MOS capacitancevoltage method is described for determining diffusion coefficients and solid solubilities in the oxide layer. Values of D ≅ 3 × 10 − 3   µ 2 / hr and N ≅ 3 × 10 18   cm − 3 were obtained for gold in SiO 2 at 1100°C.