Non-volatile memory and logic circuit process integration
View Patent ↗A method of making a logic transistor in a logic region of a substrate and a non-volatile memory cell in an NVM region of the substrate includes forming a gate dielectric layer on the substrate. A first polysilicon layer is formed on the gate dielectric. The first polysilicon layer is formed over the NVM region and removing the first polysilicon layer over the logic region. A dielectric layer is formed over the NVM region including the first polysilicon layer and over the logic region. A protective layer is formed over the dielectric layer. The dielectric layer and the protective layer are removed from the logic region to leave a remaining portion of the dielectric layer and a remaining portion of the protective layer over the NVM region. A high-k dielectric layer is formed over the logic region and the remaining portion of the protective layer. A first metal layer is formed over the high K dielectric layer. The first metal layer, the high K dielectric, and the remaining portion of the protective layer are removed over the NVM region to leave a remaining portion of the first metal layer and a remaining portion of the high K dielectric layer over the logic region. A conductive layer is deposited over the remaining portion of the dielectric layer and over the first metal layer. The NVM cell and the logic transistor are formed and this includes patterning the conductive layer.
1. A non-volatile memory cell and a logic transistor on a substrate, comprising:
a first gate dielectric comprising silicon oxide over the substrate;
a second gate dielectric of high-k material over the substrate spaced from the first gate dielectric;
a first portion of a first conductive layer over the first gate dielectric;
a first portion of a first metal layer on the second gate dielectric;
a dielectric layer over the first portion of the first conductive layer;
a first portion of a second metal layer over the first portion of the first metal layer;
a second portion of the second metal layer over the dielectric layer;
a first portion of a second conductive layer over the first portion of the second metal layer; and
a second portion of the second conductive layer over the second portion of the second metal layer.
2. The non-volatile memory of claim 1 , wherein the first metal layer and the second metal layer have the same work function.
3. The non-volatile memory of claim 1 , wherein the dielectric layer comprises a charge storage layer comprising a first insulating layer, a plurality of nanocrystals over the first insulating layer, and a second insulating layer around and over the plurality of nanocrystals.
4. The non-volatile memory of claim 1 , wherein the dielectric layer comprises a first oxide insulating layer, a silicon nitride insulating layer over the first oxide insulating layer, and a second oxide insulating layer over the silicon nitride insulating layer.
5. The non-volatile memory of claim 1 , wherein the first portion of the first conductive layer is a floating gate comprising polysilicon.
6. The non-volatile memory of claim 1 , wherein the second conductive layer comprises polysilicon.
7. A logic transistor in a logic region of a substrate and a non-volatile memory (NVM) cell in an NVM region of the substrate, comprising:
a gate dielectric on the substrate in the NVM region;
a patterned, first conductive layer on the gate dielectric in the NVM region;
a dielectric layer over the first conductive layer in the NVM region;
a high-k dielectric on the substrate in the logic region;
a first metal layer over the high-k dielectric in the logic region; and
a second conductive layer having a first portion over the dielectric layer in the NVM region and having a second portion over the first metal layer in the logic region; and
wherein the NVM cell is formed from the gate dielectric, the first conductive layer, the dielectric layer, and the first portion of the second conductive layer, and the logic transistor is formed from the high-k dielectric, the first metal layer, and the second portion of the second conductive layer.
8. The logic transistor and the NVM cell of claim 7 , wherein the first conductive layer comprises a first polysilicon layer.
9. The logic transistor and the NVM cell of claim 7 , wherein the dielectric layer comprises a charge storage layer comprising a first insulating layer, a plurality of nanocrystals over the first insulating layer, and a second insulating layer around and over the plurality of nanocrystals.
10. The logic transistor and the NVM cell of claim 7 , wherein the first conductive layer forms a floating gate.