SEMICONDUCTOR ROM DEVICE AND METHOD OF WRITING DATA

摘要

PURPOSE: To enable a ROM device to be manufactured as a product in a short term by method wherein an amorphous silicon resistor possessed of two ends, one end connected to a power supply wire and the other end connected to a drain, is selectively spot-irradiated with an ultraviolet laser beam for writing data in the ROM device. CONSTITUTION: A memory cell N of a semiconductor ROM device is composed of a MOS transistor T and two a-Si transistor SA and SB. The gate and source of the MOS transistor T of the memory cell N are connected to a word line 70 and a bit line 60 respectively. The a-Si transistor SA is connected to a power supply Vd 63, and the other a-Si transistors SB is connected to a grounding wire VSS 64. When data are written in a semiconductor ROM equipped with the above memory cell N, only the a-Si transistors SA is spot-irradiated with an ultraviolet laser beam. On the other hand, the drain of the MOS transistor T is kept at a ground potential by spot-irradiating only the a-Si transistors SB with ultraviolet rays.