NONVOLATILE MEMORY DEVICE, MEMORY SYSTEM INCLUDING THE SAME, AND METHOD OF OPERATING NONVOLATILE MEMORY DEVICE

A non-volatile memory device includes a non-volatile memory cell array including a plurality of word lines, a voltage generator configured to generate a first high-voltage using a supply voltage and a second high-voltage using an external voltage which is higher than the supply voltage, and a word line selection circuit configured. The word line selection circuit is configured apply, during a program operation of the memory cell array, the first high-voltage to a selected word line among the plurality of word lines, and the second high-voltage to unselected word lines among the plurality of word lines. 种非易失性存储器件，包括：非易失性存储器单元阵列，包括多个字线；电压产生器，配置为使用电源电压产生第高电压以及使用高于电源电压的外部电压产生第二高电压；和字线选择电路。所述字线选择电路被配置为在存储器单元阵列的编程操作期间将第高电压施加到多个字线中所选择的字线，以及将第二高电压施加到多个字线中未选择的字线。