Method for fabricating micro and nanostructures in a material

1. In a method for fabricating structures in or on a substrate through etch masking via addition or removal of a masking material and subsequent etching, a method to determine i) minimum etch mask dosage or thickness as a function of etch depth or ii) maximum etch depth as a function of etch mask implantation dosage or thickness, comprising:

determining a substrate etch rate (k etch );

determining a mask erosion rate (k erosion );

determining a threshold dose (d threshold ); and

determining a minimum etch mask thickness or dosage (d critical ) or the maximum etch depth (h critical ) according to the function

h

critical

=

k

etch

k

erosion

*

(

d

critical

-

d

threshold

)

.

2. The method of claim 1 , wherein etch masking occurs via implantation.

3. The method of claim 2 , wherein the implantation is ion implantation.

4. The method of claim 1 , wherein the etching occurs by way of a fluorinated etch chemistry.

5. The method of claim 1 , wherein the substrate is a substrate made of a group IV element or a compound of a group IV element.

6. The method of claim 5 , wherein the substrate is a silicon substrate or a carbon substrate.

7. The method of claim 5 , wherein the substrate is a silicon dioxide, graphite or diamond substrate.

8. The method of claim 5 , wherein the substrate is a silicon or silicon dioxide substrate and the etch chemistry is a fluorinated etch chemistry.

9. The method of claim 1 , wherein the addition of masking material is via Ga+ ion implantation.

10. The method of claim 9 , wherein the Ga+ ion implantation is a focused ion Ga+ ion beam implantation.

11. The method of claim 1 , wherein the addition of masking material is via a focused ion beam implantation.

12. The method of claim 4 , wherein the fluorinated etch chemistry is a combined SF 6 /C 4 F 8 etch chemistry in case of a first structure and a cryogenic fluorine (SF 6 /O 2 ) etch chemistry in case of a second structure.

13. The method of claim 12 , wherein the first structure is a nanoscale structure and the second structure is a microscale structure.

14. The method of claim 1 , wherein the substrate comprises one or more non-planar surfaces and the patterning occurs on said one or more non-planar surfaces.

15. The method of claim 14 , wherein the addition of masking material is via non-orthogonal ion implantation.

16. The method of claim 15 , wherein the non-orthogonal ion implantation occurs through inclination of the substrate with respect to an ion implantation source.

17. The method of claim 1 , wherein the substrate is silicon and the implantation is Ga+ ion implantation.

18. The method of claim 1 , wherein the addition of masking material is via ion implantation, said ion implantation forming implantation layers acting as etch masks.

19. The method of claim 1 , wherein the structures are nanoscale structures.

20. The method of claim 1 , further comprising selecting a structure size upon selection of an etching depth.

21. The method of claim 1 , wherein determining the substrate etch rate comprises measuring height of a material of the substrate after a certain amount of time during which etching is performed, and calculating a ratio between the height and the amount of time.

22. The method of claim 1 , wherein determining the mask erosion rate comprises:

implanting or depositing a set masking dose in/on a sample area;

etching the sample area until failure of masking, thus determining a time of failure; and

calculating a ratio between the masking dose and the time of failure.

23. The method of claim 1 , wherein determining the threshold dose comprises:

implanting or depositing a plurality of doses in/on a sample area;

etching the sample area for an arbitrarily small amount of time; and

determining a dose for which failure of masking occurs for said arbitrarily small amount of time.