Patent ID: 7759719

Claim:
A nonvolatile memory cell, comprising: a body of a semiconductor material having a first conductivity type; first and second spaced-apart regions formed in the body and having a second conductivity type, with a channel region of the body defined between the first and second spaced-apart regions; a charge storage layer disposed over and insulated from the channel region; a ballistic gate disposed over and insulated from the charge storage layer; and a tunneling gate disposed over and insulated from the ballistic gate by a charge filter, wherein the charge filter (i) permits transporting of charge carriers of one polarity type from the tunneling gate through the ballistic gate to the charge storage layer and (ii) blocks transporting of charge carriers of an opposite polarity type from the ballistic gate to the tunneling gate, wherein the charge filter comprises: a first dielectric disposed adjacent to the ballistic gate; and a second dielectric disposed adjacent to the first dielectric, wherein the first dielectric has an energy band gap narrower than an energy band gap of the second dielectric, and wherein the tunneling gate comprises a p+ semiconductor and the ballistic gate comprises an n+ semiconductor having an energy band gap narrower than an energy band gap of the first dielectric.