Writing of gold-doped MNOS memory devices

Gold diffusions at 900°C were carded out for diffusion times of 10, 20, and 40 min, on the MNOS devices with chemically oxidized n-type substrates. It was found that the switching speed with negative write pulses was improved 15-40 times over the control devices by 20-min gold diffusion. The writing speed is degraded with longer diffusion time because the increased accumulation of gold at the Si-SiO2interface serves effectively to increase the minority carrier relaxation time and scattering effects. It was also found that the presence of the acceptor traps and accumulation near and at the Si-SiO2interface in the MNOS system degrade the writing speed for positive pulses.