Patent ID: 8803221
Filing Date: 2014-08-12
Classification: H01L

Abstract:
1. A nonvolatile semiconductor memory device comprising: a semiconductor substrate comprising an element isolation trench; a tunnel insulating film on the semiconductor substrate; a charge storage layer on the tunnel insulating film; a block insulating film on the charge storage layer; a first element isolation insulating film in the element isolation trench, the first element isolation insulating film having a bottom surface lower in level than an interface where the semiconductor substrate and the tunnel insulating film are in contact with each other, the first element isolation insulating film having a top surface lower in level than an interface where the charge storage layer and the block insulating film are in contact with each other; a second element isolation insulating film on the first element isolation insulating film, the second element isolation insulating film protruding to a top surface of the block insulating film and being in contact with a side surface of the block insulating film, the second element isolation insulating film having a higher Si concentration than the block insulating film; and a control gate electrode on the block insulating film and on the second element isolation insulating film.