Method of forming dislocation-free strained thin films
View Patent ↗A method of forming a stressed thin film on a substrate includes forming a plurality of islands on a viscous layer that is present on a surface of a substrate. Adjacent islands are bridged with a stressor layer. The structure is annealed at an elevated temperature above the glass flow temperature of the viscous layer to transfer at least a portion of the stress from the stressor layer to the underlying islands. The bridges are then removed to expose the stressed islands of thin film on the substrate.
1. A method of forming a stressed thin film on a substrate comprising:
forming a plurality of thin film islands on a viscous layer formed on a substrate;
bridging adjacent thin film islands with a stressor layer, the stressor layer suspended above the viscous layer;
annealing the viscous layer above its glass flow temperature; and
removing the bridges.
2. The method of claim 1 , wherein the stressor layer is under compressive stress.
3. The method of claim 1 , wherein the stressor layer is under tensile stress.
4. The method of claim 1 , wherein the viscous layer comprises borophosphosilicate glass.
5. The method of claim 1 , wherein the stressor layers comprises silicon dioxide, silicon nitride, tungsten silicide, and nickel.
6. The method of claim 1 , wherein the thin film islands are substantially free from dislocations.
7. The method of claim 1 , wherein a single bridge connects two adjacent silicon thin film islands.
8. A method of forming a stressed thin film on a substrate comprising:
forming a plurality of islands on a viscous layer formed on a substrate;
providing a second substrate having a stressor layer formed thereon;
bonding the stressor layer of the second substrate to the plurality of islands;
removing the second substrate;
patterning the stressor layer to form bridges between at least a portion of adjacent islands;
annealing the viscous layer above its glass flow temperature; and
removing the bridges so as to expose stressed thin film islands.
9. The method of claim 8 , wherein the stressor layer is under compressive stress.
10. The method of claim 8 , wherein the stressor layer is under tensile stress.
11. The method of claim 8 , wherein the viscous layer comprises borophosphosilicate glass.
12. The method of claim 8 , wherein the bridges are suspended above the viscous layer.
13. The method of claim 8 , wherein the bridges are in contact with the viscous layer.
14. The method of claim 8 , wherein the stressed thin film islands are substantially free from dislocations.