Non-volatile semiconductor memory
AssigneeSharp Kabushiki Kaisha
InventorsKenichi Tanaka, Yoshimitsu Yamauchi, Keizo Sakiyama
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Abstract
A non-volatile semiconductor memory providing a semiconductor substrate including source and drain diffusion regions and a gate electrode, and an insulating film which is at least provided on the semiconductor substrate just below the gate electrode and has a smaller dielectric breakdown strength on the source side than on the drain side, wherein the insulating film is comprised of a laminated film having a multilayer structure on the drain side and a single-layer film or multilayer film which is broken down at a smaller voltage on the source side than on the drain side, and a predetermined voltage is applied to break down the single-layer film or multilayer film on the source side, so that data can electrically be written only once.
Claims6
A non-volatile semiconductor memory comprising:
- a semiconductor substrate including source and drain diffusion regions and a gate electrode, and
- an insulating film which is at least provided on the semiconductor substrate just below the gate electrode and has a portion over the source diffusion region and adjacent to an edge of the gate electrode having a dielectric breakdown strength smaller than a remaining portion of said film,
- wherein the insulating film is comprised of a laminated film having a multilayer structure on the drain side and at least a single-layer film on the source side which is broken down at a smaller voltage than said laminated film on the drain side, and a permanent conductive path between said gate electrode and said source diffusion region formed when a predetermined voltage is applied to break down said at least single-layer film on the source side, so that data can electrically be written only once.
A non-volatile semiconductor memory comprising:
- a semiconductor substrate including source and drain diffusion regions,
- a gate electrode on the semiconductor substrate between a source and a drain region and overlying at least a part of the source diffusion region, and
- an insulating film between the gate electrode and the semiconductor substrate, said film having a breakdown region at least partially below said gate electrode and partially above said source region, said breakdown region having a dielectric breakdown strength weaker than a dielectric breakdown strength of said film in a region between said gate electrode and said drain region,
- wherein a conductive path between said gate electrode and said source diffusion means is established when a permanent conductive path between said gate electrode and said source diffusion region is established when a predetermined voltage is applied to the gate electrode dielectrically to break down the insulating film on the source side, so that data can electrically be written only once.
Dependencies are inferred from the claim text.