POROUS AND NANOPOROUS SEMICONDUCTOR MATERIALS AND MANUFACTURE THEREOF

• US 20190312112A1
• Filed: 04/05/2019
• Published: 10/10/2019
• Est. Priority Date: 04/05/2018
• Status: Active Grant

• Current Assignee: Massachusetts Institute of Technology
• Original Assignee: Massachusetts Institute of Technology
• Inventors: Smith, Brendan Derek, Grossman, Jeffrey C.
• Granted Patent: US 11,004,943 B2
• Time in Patent Office: Days
• CPC Class Codes: B01D 2325/021 Pore shapes
• CPC Class Codes: B01D 2325/028 Microfluidic pore structures
• CPC Class Codes: B01D 2325/0283 Pore size
• CPC Class Codes: B01D 2325/02832 1-10 nm
• CPC Class Codes: B01D 67/0062 by micromachining techniques, e.g. using masking and etching steps, photolithography
• CPC Class Codes: B01D 67/0083 Thermal after-treatment
• CPC Class Codes: B01D 69/02 characterised by their properties
• CPC Class Codes: B01D 71/02 Inorganic material
• CPC Class Codes: B01D 71/021 Carbon
• CPC Class Codes: B01D 71/0211 Graphene or derivates thereof
• CPC Class Codes: B01D 71/0213 Silicon
• CPC Class Codes: C25F 3/02 Etching
• CPC Class Codes: H01L 21/306 Chemical or electrical treatment, e.g. electrolytic etching to form insulating layers H01L21/31
• CPC Class Codes: H01L 21/3065 Plasma etching; Reactive-ion etching
• CPC Class Codes: H01L 21/308 using masks H01L21/3063, H01L21/3065 take precedence
• CPC Class Codes: H01L 21/3081 characterised by their composition, e.g. multilayer masks, materials
• CPC Class Codes: H01L 21/324 Thermal treatment for modifying the properties of semiconductor bodies, e.g. annealing, sintering H01L21/20 - H01L21/288 and H01L21/302 - H01L21/322 take precedence
• CPC Class Codes: H01L 29/1606 Graphene
• CPC Class Codes: H01L 29/2003 Nitride compounds
• CPC Class Codes: H01L 29/24 including, apart from doping materials or other impurities, only semiconductor materials not provided for in groups H01L29/16, H01L29/18, H01L29/20, H01L29/22 including organic materials H10K99/00
• CPC Class Codes: H01L 29/32 : the imperfections being within the semiconductor body

Abstract

Methods for forming porous or nanoporous semiconductor materials are described. The methods allow for the formation of arrays pores or nanopores in semiconductor materials with advantageous pore size, spacing, pore volume, material thickness, and other aspects. Porous and nanoporous materials also are provided.

Claims

1. A porous semiconductor material comprising:

a semiconductor material; and

a plurality of pores in the semiconductor material, the plurality of pores having an average pore diameter of less than 20 nm, and wherein the plurality of pores define a total volumetric porosity, measured as the total pore volume divided by the total pore volume plus solid material volume, of at least 0.1%,

wherein at least 0.05% of the pores pass through the material from one surface to an opposite or different surface, and

wherein the material has a thickness which is the material'"'"'s minimum cross-section and which thickness is at least 0.05 micron.

2. The porous semiconductor material of claim 1, wherein the plurality of pores define a total volumetric porosity less than about 50%.

3. The porous semiconductor material of claim 2, wherein the plurality of pores define a total volumetric porosity of between about 1% and about 30%.

4. The porous semiconductor material of claim 1, wherein less than about 30% of the pores pass through the material from one surface to an opposite or different surface.

5. The porous semiconductor material of claim 4, wherein between about 0.5% and about 20% of the pores pass through the material from one surface to an opposite or different surface.

6. The porous semiconductor material of claim 5, wherein between about 1% and about 10% of the pores pass through the material from one surface to an opposite or different surface.

7. The porous semiconductor material of claim 1, wherein the material has a thickness of less than about 400 microns.

8. The porous semiconductor material of claim 7, wherein the material has a thickness of at least about 10 microns.

9. The porous semiconductor material of claim 8, wherein the material has a thickness of at least about 100 microns.

10. The porous semiconductor material of claim 9, wherein the material has a thickness of at least about 200 microns.

11. The porous semiconductor material of claim 10, wherein the material has a thickness of at least about 250 microns.

12. The porous semiconductor material of claim 1, wherein the plurality of pores are etched into the the semiconductor material.

13. The porous semiconductor material of claim 1, wherein the plurality of pores have an average inter-pore spacing of less than 10 nm.

14. The porous semiconductor material of claim 1, wherein the plurality of pores have an average aspect ratio of greater than 100:

1.

15. The porous semiconductor material of claim 1, wherein the plurality of pores have an average aspect ratio of greater than 1000:

1.

16. A method for forming a nanoporous patterned material, the method comprising:

covering a portion of a material with a nanoporous semiconductor membrane; and

etching the portion of the material through the nanoporous semiconductor membrane, wherein the nanoporous semiconductor membrane comprises pores having an average pore diameter less than 20 nm and an average aspect ratio of greater than 500;

1.

17. The method of claim 16, wherein the material comprises at least one selected from the group comprising a transition metal chalcogenide, graphene, and boron nitride.

18. The method of claim 16, further comprising thermally annealing the material after etching the portion of the material.

19. The method of claim 16, wherein etching the portion of the material comprises exposing the portion of the material to an oxygen plasma.