Highly sensitive photo-sensing element and photo-sensing device using the same

摘要

According to the present invention, a highly sensitive photo-sensing element and a sensor driver circuit are prepared by planer process on an insulating substrate by using only polycrystalline material. Both the photo-sensing element and the sensor driver circuit are made of polycrystalline silicon film. As the photo-sensing element, a photo transistor is formed by using TFT, which comprises a first electrode 11 prepared on an insulating substrate 10, a photoelectric conversion region 14 and a second electrode 12, and a third electrode 13 disposed above the photoelectric conversion region 14. An impurity layer positioned closer to an intrinsic layer (density of active impurities is 1017 cm−3 or lower) is provided on the regions 15 and 16 on both sides under the third electrode 13 or on one of the regions 15 or 16 on one side.