Radiation sensitive MOSFETs irradiated with various positive gate biases

Abstract

The RADiation sensitive metal-oxide-semiconductor field-effect-transistors (RADFETs) were irradiated with gamma rays up to absorbed dose of 110 Gy(H 2 O). The results of threshold voltage, V T , during irradiation with various positive gate biases showed the increase in V T with gate bias. The threshold voltage shift, ΔV T , during irradiation was fitted very well. The contributions of both the fixed traps (FTs) and switching traps (STs) during radiation on ΔV T were analyzed. The results show the significantly higher contribution of FTs than STs. A function that describes the dependence of threshold voltage shift and its components on gate bias was proposed, which fitted the experimental values very well. The annealing at the room temperature without gate bias of irradiated RADFETs was investigated. The recovery of threshold voltage, known as fading, slightly increase with the gate bias applied during radiation. The ΔV T shows the same changes as the threshold voltage component due to fixed states, ΔV ft , while there is no change in the threshold voltage component due to switching traps, ΔV st .

Commercial P-Channel Power VDMOSFET as X-ray Dosimeter

“…Our investigations have shown that the following simple function can fit very well the dependence of ∆V T on V G,irr, at certain dose [34].…”

“…The parameters of Equation ( 7), obtained as a result of fitting shown in Figure 3, are given in Table 3. Our investigations have shown that the following simple function can fit very well the dependence of ∆VT on VG,irr, at certain dose [34].…”

“…Another characteristic of dosimeters, in addition to sensitivity, is fading, f. This shows the recovery of the transistor threshold voltage after irradiation, during annealing at room Another characteristic of dosimeters, in addition to sensitivity, is fading, f. This shows the recovery of the transistor threshold voltage after irradiation, during annealing at room temperature without gate polarization (so-called spontaneous annealing, SA). The fading can be found as [34]…”

“…where V T (0) is the threshold voltage after irradiation, i.e., at the beginning of SA; V T (t) is the threshold voltage during SA; V T0 is the threshold voltage before irradiation; ∆V T (0) is the threshold voltage shift after irradiation, i.e., at the beginning of SA; and ∆V T (t) is the threshold voltage shift during SA. During SA after gamma irradiation, ∆V T (t) usually decreases, which gives the positive fading that increases [34]. Otherwise, ∆V T (t) can also increase (reverse annealing), giving the negative fading.…”

“…Electronics 2022, 11, x FOR PEER REVIEW 9 of 12 temperature without gate polarization (so-called spontaneous annealing, SA). The fading can be found as [34] ) 0 (…”