The gamma-ray irradiation sensitivity to radiation dose range from 0.5 Gy to
5 Gy and post-irradiation annealing at room and elevated temperatures have
been studied for p-channel metal-oxide-semiconductor field effect transistors
(also known as radiation sensitive field effect transistors or pMOS
dosimeters) with gate oxide thicknesses of 400 nm and 1 mm. The gate biases
during the irradiation were 0 and 5 V and 5 V during the annealing. The
radiation and the post-irradiation sensitivity were followed by measuring the
threshold voltage shift, which was determined by using transfer
characteristics in saturation and reader circuit characteristics. The
dependence of threshold voltage shift DVT on absorbed radiation dose D and
annealing time was assessed. The results show that there is a linear
dependence between DVT and D during irradiation, so that the sensitivity can
be defined as DVT/D for the investigated dose interval. The annealing of
irradiated metal-oxide-semiconductor field effect transistors at different
temperatures ranging from room temperature up to 150?C was performed to
monitor the dosimetric information loss. The results indicated that the
dosimeters information is saved up to 600 hours at room temperature, whereas
the annealing at 150?C leads to the complete loss of dosimetric information
in the same period of time. The mechanisms responsible for the threshold
voltage shift during the irradiation and the later annealing have been
discussed also.
In-situ tuning threshold voltage of field-effect transistors based on blends of poly(3-hexylthiophene) with an insulator electret
