Nanowire devices
A method of forming nanowire devices. The method includes forming a stressor layer circumferentially surrounding a semiconductor nanowire. The method is performed such that, due to the stressor layer, the nanowire is subjected to at least one of radial and longitudinal strain to enhance carrier mobility in the nanowire. Radial and longitudinal strain components can be used separately or together and can each be made tensile or compressive, allowing formulation of desired strain characteristics for enhanced conductivity in the nanowire of a given device.
1. A method for forming a nanowire device, comprising:
forming a semiconductor nanowire between a first support and a second support;
forming a stressor layer circumferentially surrounding the semiconductor nanowire, wherein, due to the stressor layer, the nanowire is subjected to radial strain; and
freeing the nanowire from at least one of the first support and the second support so as to further subject the nanowire to longitudinal strain to enhance carrier mobility in the nanowire.
2. The method of claim 1 , wherein the nanowire is formed by semiconducting material.
3. The method of claim 1 , wherein the nanowire is formed by semi-metal material, and wherein said strain induced by the stressor layer renders the semi-metal material semiconducting.
4. The method of claim 1 , wherein forming the stressor layer comprises material which is inherently adapted to apply stress to the nanowire.
5. The method of claim 1 , further comprising removing only the first support following forming the stressor layer.
6. The method of claim 5 , further comprising replacing the removed first support with a new support.
7. The method of claim 6 , further comprising:
removing the stressor layer from the nanowire, whereby any radial strain due to the stressor layer is eliminated, while the longitudinal strain is maintained due to the second support and the new support.
8. The method of claim 1 , wherein the stressor layer comprises a substantially homogeneous coating.
9. The method of claim 1 , wherein the nanowire comprises a rounded cross-section.
10. The method of claim 1 , wherein the stressor layer is formed at a thickness sufficient to fill a gap between the nanowire and a substrate supporting the first and second support.
11. The method of claim 10 , further comprising removing both the first support and the second support following forming the stressor layer.
12. The method of claim 11 , further comprising replacing the removed first support and second support with new supports.
13. The method of claim 12 , further comprising:
removing the stressor layer from the nanowire, whereby any radial strain due to the stressor layer is eliminated, while the longitudinal strain is maintained due to the new supports.