Low Voltage NVGTM: A New High Performance 3V/5V Flash Technology for Portable Computing and Telecommunications Applications

A new concept for a low voltage NOR Virtual Ground (NVG^TM) Flash array with a fast access time is introduced. New array concepts and process technologies are introduced to achieve programming by 5V Vpp and reading at 3V +/-10% Vcc. The array performance is enhanced by segmentation and using extra access transistor for each segment. The control of the erased cell threshold voltage distribution is one of the key issues for the 3V read operation in low voltage flash. This problem is minimized by a new erase scheme and self recovering erase techniques.