| 摘要 |
PURPOSE:To write an information with a simple construction in a read-only semiconductor memory by utilizing a neutral electron correcting center introduced into a gate insulating film, trapping thermion at semiconductor substrate side, and shifting threshold voltage of a semiconductor element toward positive direction. CONSTITUTION:A thick field oxide film 3 is formed through a field inversion preventive layer 2 on the periphery of a p-type Si substrate 1, and n-type source and drain regions 4 and 5 are formed by selective diffusion. Then, a thin fate oxide film 6 is coated on the surface of the substrate 1 as disposed between the regions 4 and 5, contact holes are perforated corresponding to the regions 4 and 5, aluminum pickup electrodes 8 and 9 are mounted therethrough, and an aluminum gate electrode 7 is coated on the residual film 6. Thereafter, it is heated in forming gas at lower than 450 deg.C for 30min to produce neutral electron collecting center 10 having a density of higher than 5X10<11>/cm<2> in the film 6. In this manner, a rectangular pulse is thereafter applied to the electrode 7 to trap the thermion from the substrate 1 toward the center 10. |
