selector gate line 31 s the bias condition will cause an electron to be injected from the bit line 61 w diffusion into the floating gate of the selected cell b 1 and cause the cell to have a high vt state this program scheme is known as fowler nordheim tunneling continuing to refer to fig1 read bit line 12 w connected to a deselected cell b 3 has a high voltage of approximately 5v applied this high voltage will reduce the voltage difference between the diffusion region of the bit line and the floating gate of the deselected cell b 3 and effectively halt the cell from being programmed for the same reason the sub bit lines 62 w and 64 w are connected to a high voltage of approximately 5 v through the source select gates s 2 and s 4 to prevent the deselected cells b 2 and b 4 from being programmed by high voltage of the word line 40 n 0066 fig1 shows the read condition for the second sector 821 when the first sector 820 is performing the program operation as described above with fig1 to read the selected cell b 5 the read select gates r 5 and r 7 are turned on by applying vdd to the select gate line 35 r this will connect the selected sub bit lines 65 r and 67 r to the read bit lines 11 r and 12 r the read bit line 11 r connects approximately 1v to the read bit line.