Thermal Sensor Using Poly-Si Thin-Film Transistors With Self-Aligned and Offset Gate Structures

We propose a thermal sensor using poly-Si thin-film transistors (TFTs) with self-aligned and offset gate structures. First, the temperature dependences of the transistor characteristic are compared between the self-aligned and offset TFTs. It is found that both the TFTs have the temperature dependence of the off-leakage current, whereas the off-leakage current of the self-aligned TFT is larger than that of the offset TFT. Next, the self-aligned and offset TFTs are included in a cell circuit to detect the temperature utilizing the off-leakage current, which is composed of a pair of 1-transistor and 1-capacitor. It is found that low and high temperatures can be detected using the self-aligned and offset TFTs, respectively. We think that it is promising to integrate this thermal sensor in certain applications using TFTs.