Structures with seeded single-crystal domains
Single-crystal devices and a method for forming semiconductor film single-crystal domains are provided. The method comprises: forming a substrate, such as glass or Si; forming an insulator film overlying the substrate; forming a single-crystal seed overlying the substrate and insulator; forming an amorphous film overlying the seed; annealing the amorphous film; and, forming a single-crystal domain in the film responsive to the single-crystal seed. The annealing technique can be (conventional) laser annealing, a laser induced lateral growth (LiLAC) process, or conventional furnace annealing. In some aspects, forming a single-crystal seed includes forming a nanowire or a self assembled monolayer (SAM). For example, a Si nanowire can be formed having a crystallographic orientation of <110> or <100>. When, the seed has a <100> crystallographic orientation, then an n-type TFT can be formed. Likewise, when a single-crystal seed has a <110> crystallographic orientation, a p-type TFT can be formed.
1. A semiconductor structure with lateral single-crystal domains, the structure comprising:
a substrate;
a first single-crystal seed having a location overlying the substrate, wherein the first single-crystal seed is a material selected from the group consisting of a nanowire (NW) and a self assembled monolayer (SAM);
a semiconductor film overlying the substrate and the first single-crystal seed, selected from the group of materials consisting of silicon (Si) and silicon germanium, the semiconductor film including a single-crystal domain extending laterally from the first single-crystal seed location.
2. The structure of claim 1 wherein the substrate is a material selected from the group consisting of glass, metal, plastic, and silicon.
3. The structure of claim 1 further comprising: an insulator film overlying the substrate and underlying the single-crystal seed, formed from a material selected from the group consisting of SiO2, SiNx, and combinations of SiO2 and SiNx.
4. The structure of claim 1 wherein the first single-crystal seed has a crystallographic orientation selected from the group consisting of <110< and <100<; and,
wherein the single-crystal domain has a crystallographic orientation that matches the first single-crystal seed.
5. The structure of claim 1 wherein the first single-crystal seed has a diameter in the range of 2 to 50 nanometers and a length in the range of 10 to 1000 microns.
6. The structure of claim 5 wherein the single-crystal domain has a width that is greater than, or equal to the length of the first single-seed crystal.
7. The structure of claim 4 further comprising:
a plurality of seed crystals overlying the substrate and underlying the single-crystal domain of the semiconductor film, having the same crystallographic orientation as the first single-seed crystal.
8. The structure of claim 1 wherein the single-crystal domain has a length greater than 50 microns.
9. The structure of claim 8 wherein the single-crystal domain has a length greater than 100 microns.
10. The structure of claim 1 further comprising:
a first plurality of single-crystal seeds overlying the substrate in a first plurality of locations; and,
a first plurality of single-crystal domains, each single-crystal domain laterally extending from a corresponding single-crystal seed location.
11. A single-crystal thin-film transistor (TFT), the TFT comprising:
a substrate;
a first single-crystal seed having a location overlying the substrate, wherein the first single-crystal seed is a material selected from the group consisting of a nanowire (NW) and a self assembled monolayer (SAM);
a semiconductor film overlying the substrate and single-crystal seed, selected from the group of materials consisting of silicon (Si) and silicon germanium, the semiconductor film including a single-crystal domain extending laterally from the first single-crystal seed location;
a TFT channel, source, and drain region formed in the single-crystal domain;
a gate oxide layer overlying the channel; and,
a gate overlying the gate oxide layer.
12. The TFT of claim 11 wherein the first single-crystal seed and the single-crystal domain have a <100> crystallographic orientation;
wherein the source and drain are n+ doped.
13. The TFT of claim 11 wherein the first single-crystal seed and the single-crystal domain have a <110> crystallographic orientation;
wherein the source and drain are p+ doped.
14. The TFT of claim 11 further comprising:
a plurality of single-crystal seeds, each having a location overlying the substrate;
a plurality single-crystal domains, each extending laterally from a corresponding single-crystal seed location;
a TFT channel, source, and drain region formed in each single-crystal domain;
a gate oxide layer overlying each channel; and,
a gate overlying each gate oxide layer.
15. The TFT of claim 11 further comprising:
a plurality of TFT channel, source, and drain regions formed in the single-crystal domain;
a gate oxide layer overlying each channel; and,
a gate overlying each gate oxide layer.
16. The structure of claim 11 wherein the substrate is a material selected from the group consisting of glass, metal, plastic, and silicon.
17. The structure of claim 11 further comprising:
an insulator film overlying the substrate and underlying the first single-crystal seed, formed from a material selected from the group consisting of SiO2, SiNx, and combinations of SiO2 and SiNx.
18. The TFT of claim 11 wherein the first single-crystal seed has a crystallographic orientation selected from the group consisting of <110> and <100>; and,
wherein the single-crystal domain has a crystallographic orientation that matches the first single-crystal seed.
19. The TFT of claim 11 wherein the first single-crystal seed has a diameter in the range of 2 to 50 nanometers and a length in the range of 10 to 1000 microns.
20. The TFT of claim 19 wherein the single-crystal domain has a width that is greater than, or equal to the length of the first single-seed crystal.
21. The TFT of claim 18 further comprising:
a plurality of seed crystals overlying the substrate and underlying the single-crystal domain of the semiconductor film, having the same crystallographic orientation as the first single-seed crystal.
22. The TFT of claim 11 wherein the single-crystal domain has a length greater than 50 microns.
23. The TFT of claim 22 wherein the single-crystal domain has a length greater than 100 microns.