Patent ID: 7332768

Claim:
A non-volatile memory (NVM) device comprising: a charge supply region; a non-conductive charge storage region; an insulating barrier extending between the charge supply region and the charge storage region; and one or more structures used to establish an electric field over the insulating barrier for tunneling charge carriers from the charge supply region to the charge storage region, wherein the insulating barrier comprises: a first portion contacting the charge supply region; and a second portion contacting the first portion and extending towards the charge storage region, wherein: the first portion is substantially thinner than the second portion; the first and second portions are each constructed using respective one or more tunneling dielectric materials, the respective one or more tunneling dielectric materials of the first and second portions being selected such that the first portion has, on average, a lower dielectric constant than the second portion; and the first and second portions have respective thicknesses, the respective thicknesses being selected so as to allow for tunneling of negative and positive charge carriers from the charge supply region to the charge storage region.