Semiconductor memory device and writing method thereof

A writing method of a semiconductor memory device, the semiconductor memory device comprising:

• a memory cell array including memory transistors each including a gate insulating film formed on a semiconductor substrate, a gate electrode formed on the gate insulating film, and a variable resistance film formed on the gate electrode and made of a variable resistance material having a variable resistance value, the memory cell array being configured by a plurality of memory strings each including plural ones of the memory transistors connected in series, the memory strings being disposed with their longer direction extending in a first direction;
• word lines disposed with their longer direction extending in a second direction orthogonal to the first direction, and each connected commonly to the gate electrodes of plural ones of the memory transistors lined up in the second direction;
• a plate line disposed to sandwich the variable resistance film between itself and the gate electrode;
• a plurality of first voltage terminals configured to supply a certain voltage to first ends of the plurality of memory strings, respectively;
• and
• a plurality of second voltage terminals configured to supply a certain voltage to second ends of the plurality of memory strings, respectively,
• the method comprising setting the word line connected to a memory transistor to be written to a floating state, while supplying the remaining word lines with a first voltage,
• a potential difference between the first voltage and a second voltage supplied to the plate line being smaller than a voltage to be applied to the variable resistance film for changing the resistance value of the variable resistance film.