Patent ID: 8450714

Claim:
A semiconductor memory device comprising: a first conductive line extending in a first direction; a second conductive line extending in a second direction crossing the first direction; a cell unit comprising a phase-change film and a diode including a p-type semiconductor layer and an n-type semiconductor layer which are connected in series between the first conductive line and the second conductive line; a silicon nitride film formed on a side surface of the phase-change film, a bottom surface of the silicon nitride film being lower than a top surface of the diode; and an insulating film which is formed on a side surface of the diode and has a smaller amount of charge trapping than the silicon nitride film; wherein, when a boundary between the phase-change film and the silicon nitride film on the side surface of the phase-change film and the diode is cut along a plane parallel to the first direction and the second direction, a cross-sectional area of the phase-change film and the silicon nitride film is equal to a cross-sectional area of the diode.