Nonvolatile semiconductor memory device and fabrication method therefor

A nonvolatile semiconductor memory device comprises source/drain regions (111), which are disposed separated from one another in the surface region of a semiconductor substrate (101), a tunnel insulating film (102), which is disposed on the channel between the source/drain regions (111), a charge storage layer (103), which his disposed on the tunnel insulating film (102), a first dielectric film (105), which is disposed on the charge storage layer (103), and contains a lanthanum aluminum silicon oxide or oxynitride, a second dielectric film (106), which is disposed on the first dielectric film (105), and contains an oxide or oxynitride that contains at least one of hafnium (Hf), zirconium (Zr), titanium (Ti), and rare earth metal, and a control gate electrode (107), which is disposed on the second dielectric film (106).