Buried source-side injection (BSSI) for flash EPROM programming

A flash-EPROM cell structure that can be programmed at low drain voltages and low power is disclosed. The new element in the device structure is the incorporation of buried junction at the source side where the high electric field region is established during programming. The cell is programmed by hot-electron injection at the source side and erased by Fowler-Nordheim tunneling at the drain side. Typical programming time of 10 μs/byte can be accomplished with 3.5 V on the drain junction. The structure can be built with the standard EPROM technology and can offer advantages in low-voltage power supply systems such as portable and notebook computers