Mechanism and Performance of Floating-Gate a-Si:H TFT Nonvolatile Memory evices

摘要

Conventionally, the amorphous silicon thin film transistor (a-Si:H TFT) is used to switch the liquid crystal layer at each pixel of the liquid crystal display (LCD). It has also been applied to read out charges stored in the diode of each pixel in an x-ray imager. It has been reported that several a-Si:H TFTs can be used together to drive the organic light emitting diode (OLED) device. There are demonstrations on the successful application of a-Si:H TFTs in chemical and biological sensing. In these applications, the a-Si:H TFT is used as a local switching device. In many cases, if the a-Si:H TFT can be made into a memory device, new functions can be introduced into the product to greatly expand the application range. Recently, the author's group demonstrated that the floating-gate a-Si:H TFT and capacitor can be fabricated into nonvolatile memories (1-5). Since the whole device is made from the same thin film materials as those of the conventional a-Si:H TFT, it is easily integrated into displays, sensors, imagers, etc. on various low-temperature rigid or flexible substrates. Just like the TFT LCD fabrication, there is almost no substrate size limitation.