Non-volatile semiconductor memory device

A method of controlling a non-volatile semiconductor memory device in a read operation thereof, the non-volatile semiconductor memory device comprising:

• a first memory string including a first memory cell and a second memory cell;
• a second memory string including a third memory cell and a fourth memory cell;
• a first word line electrically connected to a gate of the first memory cell and a gate of the third memory cell;
• a second word line electrically connected to a gate of the second memory cell and a gate of the fourth memory cell;
• a bit line electrically connected to one end of the first memory string and one end of the second memory string;
• a first source line electrically connected to the other end of the first memory string;
• and
• a second source line electrically connected to the other end of the second memory string,
• wherein the non-volatile semiconductor memory device includes a plurality of memory cells, the plurality of memory cells being stacked above a semiconductor substrate, the plurality of memory cells including the first memory cell, the second memory cell, the third memory cell and the fourth memory cell,
• in the read operation, the method comprising:
• performing a read operation for the first memory cell on the condition that a first voltage is applied to the first word line, a second voltage is applied to the second word line, a third voltage is applied to the bit line, a fourth voltage is applied to the first source line, a fifth voltage is applied to the second source line, the second voltage is higher than the first voltage and the fourth voltage is different from the fifth voltage.