Dual channel memory
Technologies are generally described related to a dual channel memory device, system and method of manufacture. Various described devices include utilization of both a front channel and a back channel through a substrate formed underneath a dual gate structure of a semiconductor device. Using two pairs of contacts on opposing sides of the gate structure, where the contact pairs are formed on differently doped layers of the semiconductor device, multiple bits may be stored in the semiconductor device acting as a single memory cell. Memorization may be realized by storing different amount or types of charges on the floating gate, where the charges may impact a conduction status of the channels of the device. By detecting the conduction status of the channels, such as open circuit, close circuit, or high resistance, low resistance, data stored on the device (“0” or “1”) may be detected.
1. A semiconductor device, comprising:
a first substrate; and
a vertical gate structure positioned over the first substrate, wherein the vertical gate structure comprises:
a fin structure that has a bottom surface in contact with a centrally located first portion of the first substrate;
a tunnel oxide layer configured to cover at least one vertical surface of the fin structure;
a floating gate layer configured to cover at least one surface of the tunnel oxide layer;
a control oxide layer configured to cover at least one surface of the floating gate layer; and
a control gate layer configured to cover at least one surface of the control oxide layer, wherein the control gate layer comprises:
a first section configured to control a first conduction channel of the semiconductor device within the first substrate that corresponds to a first conduction path between a source layer and a drain laver: and
a second section configured to control a second conduction channel of the semiconductor device within the first substrate that corresponds to a second conduction path between the source layer and the drain layer.
2. The semiconductor device of claim 1 , wherein the source layer and the drain layer are located on opposite sides of the vertical gate structure, and wherein bottom surfaces of the source layer and the drain layer are configured to contact the first substrate.
3. The semiconductor device of claim 2 , wherein:
the source layer includes at least two regions,
the drain layer includes at least two other regions, and
the at least two regions of the source layer and the at least two other regions of the drain layer are doped with dopants of an opposite polarity.
4. The semiconductor device of claim 3 , further comprising:
a first pair of contacts configured to contact the at least two regions of the source layer; and
a second pair of contacts configured to contact the at least two other regions of the drain layer.
5. The semiconductor device of claim 3 , wherein the dopants of the opposite polarity include p dopants and it dopants.
6. The semiconductor device of claim 1 , wherein the semiconductor device is implemented as pan of a vertical fin-shaped, field effect transistor (FINFET) structure.
7. The semiconductor device of claim 1 , further comprising:
a nitride hard mask formed substantially around and over the control gate layer, wherein the nitride hard mask is utilized to protect the control gate layer during a thinning of a portion of a second substrate.
8. The semiconductor device of claim 1 , wherein
the first section and the second section have opposite polarities, and wherein the first section is electrically decoupled from the second section.
9. The semiconductor device of claim 1 , further comprising:
a nitride hard mask formed substantially around and over the control gate layer, wherein the nitride hard mask is utilized to pattern one or more gates of the fin structure.
10. A system configured to operate a dual channel memory device, the system comprising:
a controller configured to selectively activate or deactivate conduction paths that correspond to one or more of a first conduction path and a second conduction path; and
the dual channel memory device coupled to the controller, wherein the dual channel memory device comprises:
a first substrate;
a vertical gate structure positioned over the first substrate, wherein the vertical gate structure comprises:
a fin structure that has a bottom surface in contact with a centrally located first portion of the first substrate;
a tunnel oxide layer configured to cover at least one vertical surface of the fin structure;
a floating gate layer configured to cover at least one surface of the tunnel oxide layer;
a control oxide layer configured to cover at least one surface of the floating gate layer; and
a control gate layer configured to cover at least one surface of the control oxide layer, wherein the control gate layer comprises:
a first section configured to control a first conduction channel of the dual channel memory device within the first substrate that corresponds to the first conduction path, which is between a source layer and a drain layer; and
a second section configured to control a second conduction channel of the dual channel memory device within the first substrate that corresponds to the second conduction path, which is between the source layer and the drain layer.
11. The system of claim 10 , wherein the controller is further configured to:
store different information in the dual channel memory device by one of
deactivation of the first conduction path and activation of the second conduction path;
deactivation of the first conduction path and the second conduction path; and
activation of the first conduction path and deactivation of the second conduction path.
12. The system of claim 10 , wherein:
the first conduction channel of the dual channel memory device and the second conduction channel of the dual channel memory device are biased with substantially a same bias voltage selected by the controller.
13. The system of claim 10 , wherein:
the first conduction channel of the dual channel memory device and the second conduction channel of the dual channel memory device are biased with different bias voltages selected by the controller, and
the controller is configured to select the different bias voltages such that at least one of the first conduction channel of the dual channel memory device and the second conduction channel of the dual channel memory device operates in a reverse bias mode.
14. A method to fabricate a semiconductor device, the method comprising:
forming a first substrate; and
forming a vertical gate structure positioned over the first substrate, wherein forming the vertical gate structure comprises:
forming a fin structure that has a bottom surface in contact with a centrally located first portion of the first substrate;
forming a tunnel oxide layer configured to cover at least one vertical surface of the fin structure;
forming a floating gate layer configured to cover at least one surface of the tunnel oxide layer,
forming a control oxide layer configured to cover at least one surface of the floating gate layer; and
forming a control gate layer configured to cover at least one surface of the control oxide layer, wherein forming the control gate layer comprises:
forming a first section configured to control a first conduction channel of the semiconductor device within the first substrate that corresponds to a first conduction path between a source layer and a drain layer: and
forming a second section configured to control a second conduction channel of the semiconductor device within the first substrate that corresponds to a second conduction path between the source layer and the drain layer.
15. A semiconductor device, comprising:
a first substrate;
a vertical gate structure positioned over the first substrate, wherein the vertical gate structure comprises a tin structure, a tunnel oxide layer, a floating gate layer, a control oxide layer, and a control gate layer; and
a source layer and a drain layer located on opposite sides of the vertical gate structure, wherein:
the source layer includes at least two regions and the drain layer includes at least two other regions, and
the at least two regions of the source layer and the at least two other regions of the drain layer are doped with dopants of an opposite polarity to form a first conduction channel and a second conduction channel.