Non-volatile memory cell with oxide and nitride tunneling layers

Abstract

A non-volatile memory cell structure capable of being programmed by band-to-band tunneling induced substrate hot electron injection is formed in a semiconductor substrate 8 and comprises first 10 and second 12 highly doped regions separated by a channel region 14. A nitride layer 16, such as silicon nitride for example, is formed over the channel region 14. An oxide layer 18, such as silicon dioxide, is then formed over nitride layer. The oxide/nitride layer serves as the floating gate insulator. In another embodiment, an additional oxide layer 15 may be formed between the channel region 14 and the nitride layer 16. The floating gate 20 is formed over the oxide layer 16 and a control gate 24 is insulatively formed over the floating gate 20. Other variations, advantages and a fabrication method are also disclosed.