Nanocrystal non-volatile memory cell and method therefor
View Patent ↗A method of forming a semiconductor device includes forming a first dielectric layer over a semiconductor substrate, forming a plurality of discrete storage elements over the first dielectric layer, thermally oxidizing the plurality of discrete storage elements to form a second dielectrics over the plurality of discrete storage elements, and forming a gate electrode over the second dielectric layer, wherein a significant portion of the gate electrode is between pairs of the plurality of discrete storage elements. In one embodiment, portions of the gate electrode is in the spaces between the discrete storage elements and extends to more than half of the depth of the spaces.
1. A semiconductor device comprising:
a first discrete storage element over a semiconductor substrate having a first height;
a second discrete storage element over the semiconductor substrate having a second height, wherein the first discrete storage element and the second discrete storage element are separated by a space; and
the space has a depth;
a first dielectric over the first discrete storage element and within the space;
a second dielectric over the second discrete storage element and within the space; and
a first portion of a gate electrode extending below the first height and the second height and between the first dielectric and the second dielectric, wherein the first portion extends within the space more than half of the depth.
2. The semiconductor device of claim 1 , wherein the first portion of the gate electrode between the first dielectric and the second dielectric has a lateral dimension that is approximately 5 to approximately 10 nanometers.
3. The semiconductor device of claim 1 , wherein the first dielectric has a first lateral dimension and the second dielectric has a second lateral dimension, wherein the first lateral dimension and the second lateral dimension are approximately 5 nanometers to approximately 10 nanometers.
4. The semiconductor device of claim 1 , further comprising:
a plurality of discrete storage elements over the semiconductor substrate, wherein the first discrete storage element and the second discrete storage element are portion of the plurality of discrete storage elements;
dielectrics over each of the plurality of discrete storage elements, wherein the dielectrics include the first dielectric and the second dielectric; and
portions of the gate electrode substantially between adjacent pairs of the plurality of discrete storage elements and their associated dielectrics, wherein the portions of the gate electrode include the first portion of the gate electrode.
5. The semiconductor device of claim 1 , further comprising a tunnel dielectric over the semiconductor substrate, wherein the first discrete storage element and the second discrete storage element are over the tunnel dielectric.
6. The semiconductor device of claim 5 , further comprising:
a layer comprising nitride over the tunnel dielectric; and
a third dielectric over the first dielectric and the second dielectric, wherein the first portion of the gate electrode is over a first portion of the third dielectric and between a second portion and a third portion of the third dielectric.
7. The semiconductor device of claim 6 , wherein:
the tunnel dielectric comprises a material selected from the group consisting of silicon dioxide, silicon oxynitride, hafnium oxide, aluminum oxide, and hafnium zirconate;
the first discrete storage element comprises an element selected from the group consisting of silicon, germanium, and aluminum;
the second discrete storage element comprises an element selected from the group consisting of silicon, germanium, and aluminum; and
third dielectric comprises a material selected from the group consisting of silicon dioxide, aluminum oxide, tantalum pentoxide, and hafnium oxide.