SUMMARYDesign rules are presented for the suppression of photocurrents generated in the depletion layers of the channel/drain junction regions of low-temperature poly-Si thin-film transistors (TFTs). Device simulation based on modeling the behavior of the density of states in a low-temperature poly-Si TFT was used to find the width of the junction depletion layer. These simulations show that in order to suppress photocurrents to below 6 pA, the LDD region must have a sheet resistance in the range of 30 and 70 kΩ/", which forces its length to exceed 1 µm.