Patent ID: 7169671
Filing Date: 2007-01-30
Classification: G11C,H01L,Y10S

Abstract:
1. A method of recording information in a nonvolatile semiconductor memory, after erasing information in the nonvolatile semiconductor memory by charge accumulation, said nonvolatile semiconductor memory including: a substrate of a first conductivity type; a transistor having a control electrode provided on said substrate with a first insulating film intervening, and a first main electrode region and second main electrode region which are a pair of diffusion regions provided in a surface region of the substrate, with impurities of a second conductivity type differing from said first conductivity type, said control electrode being located between said first and second main electrode regions; a channel formation region formed in said substrate and opposing said control electrode over the first insulating film; a first resistance-change portion of said second conductivity type, provided in the surface region of said substrate between one of said first and second main electrode regions and said channel formation region, an impurity concentration of said first resistance-change portion being lower than that of said one of first and second main electrode regions; and, a first charge accumulation portion provided on the first resistance-change portion, the first charge accumulation portion having a first insulating layer and capable of accumulation of charge; wherein when said first conductivity type is a p type and said second conductivity type is an n type, said method comprises: applying a high positive voltage to said one of said first and second main electrode regions; setting the other of said first and second main electrode regions to ground voltage; and, applying a positive voltage to said control electrode to cause weak inversion of said channel formation region; and, when said first conductivity type is the n type and said second conductivity type is the p type, said method comprises: applying a high negative voltage to said one of said first and second main electrode regions; setting the other of said first and second main electrode regions to the ground voltage; and, applying a negative voltage to said control electrode to cause the weak inversion of said channel formation region.