New technique for measuring the ionizing radiation effects in metal oxide semiconductor transistors

Abstract

A simple technique based on the measurement of gate induced drain leakage current (Idl) is developed to measure the radiation induced charge in the metal oxide semiconductor transistor. After irradiation Idl of n-channel MOS transistors decreases while that of p-channel devices increases. The change of leakage current at higher tunneling fields is proportional to the increase of hole trap density in the gate oxide region. The leakage current measurement technique is an useful tool for characterizing radiation effects in MOS transistors because at high biases Idl is dependent on the increase of oxide charge while independent of the interface states. It depends on gate and drain overlap geometry and independent of the channel length. Hence Idl measurement technique is advantageous over threshold voltage technique which depends on the channel length.