Offset independently operable VTFT electrodes
A multiple vertical transistor device includes a polymeric material post on a substrate. An inorganic material cap extends beyond first and second edge of the post to define first and second reentrant profiles. First and second portions of a conformal conductive gate layer define first and second gates in the first and second reentrant profiles, respectively. A conformal electrically insulating layer maintains the first and second reentrant profiles and is in contact with the first and second gates. First and second portions of a semiconductor layer, maintaining the first and second reentrant profiles, are in contact with the conformal electrically insulating layer that is in contact with the first and second gates, respectively. The first and second portions of the semiconductor layer are electrically independent from each other. First and second electrodes are associated with the first gate. Third and fourth electrodes are associated with the second gate.
1. A device including two vertical transistors comprising:
a substrate;
a polymeric material post on the substrate, the post having a height dimension extending away from the substrate to a top, the post having a first edge and a second edge located opposite the first edge along the height dimension;
an inorganic material cap on the top of the post, the cap covering the top of the post, the cap extending beyond the first edge to define a first reentrant profile and extending beyond the second edge to define a second reentrant profile;
a conformal conductive gate layer, a first portion of the conformal conductive gate layer defining a first gate located in at least the first reentrant profile, a second portion of the conformal conductive gate layer defining a second gate that is electrically independent from the first gate and located in at least the second reentrant profile;
a conformal electrically insulating layer that maintains the first and second reentrant profiles and is in contact with the first gate and the second gate and at least a portion of the substrate;
a conformal semiconductor layer including a first portion and a second portion, the first portion of the semiconductor layer maintaining the first reentrant profile and in contact with the conformal electrically insulating layer that is in contact with the first gate, the second portion of the semiconductor layer maintaining the second reentrant profile and in contact with the conformal electrically insulating layer that is in contact with the second gate, the first portion of the semiconductor layer and the second portion of the semiconductor layer being electrically independent from each other;
a first electrode and a second electrode associated with the first gate, the first electrode in contact with the first portion of the semiconductor layer and located adjacent to the first edge, a second electrode over the inorganic material cap and in contact with the first portion of the semiconductor layer, the first electrode and the second electrode defining a first channel associated with the first gate of a first transistor; and
a third electrode and a fourth electrode associated with the second gate, the third electrode in contact with the second portion of the semiconductor layer and located adjacent to the second edge, a fourth electrode over the inorganic material cap and in contact with the second portion of the semiconductor layer, the third electrode and the fourth electrode defining a second channel associated with the second gate of a second transistor.
2. The device of claim 1 , the first electrode and the second electrode defining ends of the first channel, the third electrode and the fourth electrode defining ends of the second channel, wherein a first line extending between the ends of the first channel is not parallel to a second line extending between the ends of the second channel.
3. The device of claim 1 , wherein the electrically insulating material layer has uniform thickness.
4. The device of claim 1 , wherein the first portion of the semiconductor material layer and the second portion of the semiconductor material layer have a uniform thickness.
5. The device of claim 1 , wherein the first electrode, the second electrode, the third electrode, and the fourth electrode have the same material composition and layer thickness.
6. The device of claim 1 , wherein the substrate is flexible.
7. The device of claim 1 further comprising:
a conformal dielectric material layer on the cap, the edges of the post, and at least a portion of the substrate, the conformal dielectric layer being located at least between the first gate and the post, and the second gate and the post.
8. The device of claim 1 , wherein the first electrode, the second electrode, the third electrode, and the fourth electrode are transparent conductive oxides.
9. The device of claim 1 , wherein the post comprises an epoxy resin or polyimide.
10. The device of claim 1 , wherein the cap extends beyond the edge of the post by a distance that is less than the height of the post.
11. The device of claim 1 , further comprising another conductive material layer positioned at least under a portion of the polymeric material post and in electrical contact with the first gate and not in contact with the second gate.