The Electrical Bias Influence on the Total Ionizing Dose Degradation of the MOST Parameters

Abstract

power MOSFET are widely used in spacecraft equipment set. During the lifetime, which reaches 15 years or more for modern and promising spacecrafts, in space radiation environment the equipment is exposed to significant impacts of total ionizing dose (TID) effects, which leads to degradation of the parameters of the electronic components used, this may lead to the loss of the spacecraft and early termination of the space mission. In this case, the rate of TID-degradation of the parameters is largely depends on the electrical mode of the components during the irradiation.The article considers the influence of various electrical modes of the gate of a power n-channel MOSFET on the rate of TID-degradation of one of the most radiation-sensitive parameters – the threshold voltage [1], [2]. Investigations were carried out in the following electrical modes: constant gate-source voltage in the range from −20 V to +20 V; rectangular signals with different values of frequency, duty cycle, as well as with different values of the upper and lower voltage levels. During the irradiation process, the dependence of the drain current on the gate-to-source voltage was periodically monitored for each sample, the shift of which to the area of negative values of the gate-to-source voltage made it possible to evaluate the transistor TID-hardness in each of the considered modes.The results of investigations allow identifying the most critical electric mode n-channel MOSFET with ionizing radiation of outer space, as well as to assess the strength level of the transistor during irradiation in one of the studied conditions based on data on persistence, defined in the most critical mode [3].