Embodiments of the present invention relate to an electronic device and, more particularly, to a semiconductor memory device and a program method thereof.
A semiconductor memory device is a storage device that is realized using semiconductor such as silicon (Si), germanium (Ge), gallium arsenide (GaAs), or indium phosphide (InP). Semiconductor memory devices are classified into volatile memory devices and nonvolatile memory devices.
A volatile memory device is a memory device that loses its stored data when power supply is off. The volatile memory device may include a static random access memory (SRAM) device, a dynamic RAM (DRAM) device, a synchronous DRAM (SDRAM) device, or the like. A non-volatile memory device is a memory device that retains its stored data even when not powered. The non-volatile memory may include a read only memory (ROM) device, a programmable ROM (PROM) device, an electrically programmable ROM (EPROM) device, an electrically erasable and programmable ROM (EEPROM) device, a flash memory device, a phase-change RAM (PRAM) device, a magnetic RAM (MRAM) device, a resistive RAM (RRAM) device, a ferroelectric RAM (FRAM) device, or the like. The flash memory device is classified into a NOR type and a NAND type.
During program of a semiconductor memory device, a verify operation and a program operation may be repeated. When each of the verify operation and the program operation is performed, corresponding voltages are applied to word lines coupled to a memory cell array. In order to change voltage levels of the corresponding voltages to desired voltage levels in each of the verify operation and the program operation, precharge and discharge operations need to be performed during the program of the semiconductor memory device, and thus a predetermined amount of time is required to perform the precharge and discharge operations. As a result, as a time taken to perform the precharge and discharge operations increases, a program speed of the semiconductor memory device may increase.