A Single Device Temperature Sensor Based on Amorphous Silicon Thin Film Transistor

Abstract

A single device temperature sensor based on amorphous silicon thin film transistor (a-Si TFT) is proposed. First, we measured the transfer characteristics of a-Si TFTs with different sizes in the operating temperature range (220 K, 248 K, 273 K, 298 K, 323 K, and 345 K). Measurements indicate that the drain current of ON-state a-Si TFTs is sensitive to the change of ambient temperature. There is an obvious exponential relationship between drain current and ambient temperature. Next, the principle of temperature dependence of drain current was analyzed, and the temperature dependence with different channel sizes and bias voltages was compared. On this basis, the linear relationship between the logarithm of drain current and the reciprocal of temperature was established by piecewise fitting. The fitting results show that the relationship has good linearity and sensitivity at 220K–323K and can be well applied to a-Si TFTs of different sizes. Finally, according to the established linear relationship, we gave a sensing scheme to realize the measurement of temperature. It is significant to use a-Si TFT as temperature sensor to detect the ambient temperature of devices and circuits in many fields.