NON-VOLATILE SEMICONDUCTOR MEMORY

摘要

A non-volatile semiconductor memory has a tunnel insulating film (110) on a channel region (101) formed in a semiconductor substrate (100) and a charge storage layer (130) formed on the tunnel insulating film (110). The tunnel insulating film (110) comprises: a first fine-grain layer (121) including first conductive fine grains and provided on the channel side; and a second fine-grain layer (122) including second conductive fine grains having an average grain diameter greater than that of the first conductive fine grains and provided on the charge storage layer side. An average value (?E1) of energy required for charging a single electron in the first conductive fine grains is made less than an average value (?E) of energy required for charging a single electron in the second conductive fine grains, and the difference between ?E1 and ?E is made greater than the thermal fluctuation energy (kBT).