Non-volatile semiconductor memory device
View Patent ↗Provided is a small-area one-time programmable semiconductor memory device that uses a PNPN structure, which is parasitically generated in a CMOS process. An N-type region provided in a location other than both ends or a P-type region provided in a location other than both the ends is put into a floating state so that PNPN current flows, and a thermal breakdown of a resistor caused by this current is used as a memory element.
1. A non-volatile semiconductor memory device, comprising:
a first first-conductivity-type region provided in a semiconductor substrate;
a first second-conductivity-type region in contact with the first first-conductivity-type region;
a second second-conductivity-type region formed in the first first-conductivity-type region; and
a second first-conductivity-type region formed in the first second-conductivity-type region,
the first first-conductivity-type region being electrically connected to a second-conductivity-type potential which corresponds to VSS when the second-conductivity-type potential is N-type potential and which corresponds to VDD when the second-conductivity-type potential is P-type potential,
the second first-conductivity-type region being connected to a first-conductivity-type potential which corresponds to VSS when the first-conductivity-type potential is N-type potential and which corresponds to VDD when the first-conductivity-type potential is P-type potential via a resistor,
the first second-conductivity-type region being connected to the first-conductivity-type potential via a switch, the first second-conductivity-type region being electrically connected to the first-conductivity-type potential after turning on of the switch, and the first second-conductivity-type region entering a floating state after turning off of the switch,
writing of data being prevented when current being injected from the second second-conductivity-type region with the switch turned on, and
writing of data being performed with use of flow of PNPN current when the current being injected from the second second-conductivity-type region with the switch turned off.
2. A non-volatile semiconductor memory device according to claim 1 , wherein the second second-conductivity-type region comprises one of an second-conductivity-type region of an ESD protection element and an second-conductivity-type region of an second-conductivity-type output transistor.
3. A non-volatile semiconductor memory device according to claim 1 , wherein the switch is normally on.
4. A non-volatile semiconductor memory device according to claim 1 , wherein the non-volatile semiconductor memory device has a write inhibition mode function.
5. A non-volatile semiconductor memory device, comprising a plurality of the non-volatile semiconductor memory devices of claim 1 ,
wherein the plurality of the non-volatile semiconductor memory devices share the first first-conductivity-type region and the second second-conductivity-type region.
6. A non-volatile semiconductor memory device according to claim 1 , wherein a thermal breakdown of the resistor occurs in writing the data.
7. A non-volatile semiconductor memory device according to claim 1 , wherein the resistor is bent at least twice in a planar view.
8. A non-volatile semiconductor memory device according to claim 1 , wherein the resistor is made of polysilicon.
9. A non-volatile semiconductor memory device according to claim 1 , wherein the resistor comprises an interconnection for connecting different wiring layers to each other.
10. A non-volatile semiconductor memory device according to claim 9 , wherein a thermal breakdown of a wiring region in contact with the interconnection for connecting different wiring layers to each other occurs in writing the data.
11. A non-volatile semiconductor memory device according to claim 1 , wherein the second first-conductivity-type region is surrounded by a high-concentration second-conductivity-type region in a planar view, the high-concentration second-conductivity-type region having the same polarity as a polarity of the first second-conductivity-type region.
12. A non-volatile semiconductor memory device according to claim 1 , wherein a thermal breakdown of a PN junction portion occurs in writing the data.