Charge separation technique for metal–oxide–silicon capacitors in the presence of hydrogen deactivated dopants

Abstract

An improved charge separation technique for metal–oxide–silicon (MOS) capacitors is presented which accounts for the deactivation of substrate dopants by hydrogen at elevated irradiation temperatures or small irradiation biases. Using high-frequency capacitance–voltage measurements, radiation-induced inversion voltage shifts are separated into components due to oxide trapped charge, interface traps, and deactivated dopants, where the latter is computed from a reduction in Si capacitance. In the limit of no radiation-induced dopant deactivation, this approach reduces to the standard midgap charge separation technique used widely for the analysis of room-temperature irradiations. The technique is demonstrated on a p-type MOS capacitor irradiated with Co60 γ rays at 100 °C and zero bias, where the dopant deactivation is significant.