METHOD OF MANUFACTURING LATERALLY GRADED POROUS SILICON OPTICAL FILTER THROUGH DIFFUSION-LIMITED ETCHING AND FILTER STRUCTURE MANUFACTURED THEREBY

• US 20090087143A1
• Filed: 08/15/2008
• Published: 04/02/2009
• Est. Priority Date: 09/28/2007
• Status: Active Grant

• Current Assignee: Samsung Electronics Co. Ltd., Seoul National University Industry Foundation (Seoul National University)
• Original Assignee: Samsung Electronics Co. Ltd., Seoul National University Industry Foundation (Seoul National University)
• Inventors: HWANG, Kyung Wook, JEON, Heon Su
• Granted Patent: US 8,540,862 B2
• Time in Patent Office: Days
• US Class Current: 385/37
• CPC Class Codes: B29D 11/00634 Production of filters
• CPC Class Codes: G02B 5/20 Filters polarising elements G02B5/30

Abstract

Disclosed herein is a method of manufacturing a laterally graded porous silicon optical filter through diffusion-limited etching. The change in resonance frequency of the porous silicon layer in a taper axis direction is adjusted using the diffusion of reactive ions in an etchant under conditions of use of a related etch mask pattern. It is possible to manufacture an optical band-pass filter having a resonance frequency that linearly changes using a tapered etch window opening.

Claims

1. A method of manufacturing a laterally graded porous silicon optical filter through diffusion-limited etching, comprising:

forming an etch mask; and

conducting anodic etching in a porous silicon etch bath.

2. The method of claim 1, wherein the etch mask has a tapered etch window opening, a width of which is gradually decreased from one end toward the other end along an axis of the tapered etch window opening.

3. The method of claim 2, wherein the tapered etch window opening includes a tapered shape, which extends in an axial direction thereof, such that the tapered etch window opening has a predetermined degree of taper between both ends thereof, and each of both lateral sides of the tapered shape is formed linearly.

4. The method of claim 2, wherein the tapered etch window opening has a tapered shape, which extends in an axial direction thereof, such that the tapered etch window opening has a predetermined degree of taper between both ends thereof, and each of both lateral sides of the tapered shape is formed to be outwardly parabolic.

5. The method of claim 2, wherein the tapered etch window opening has a tapered shape, which extends in an axial direction thereof, such that the tapered etch window opening has a predetermined degree of taper between both ends thereof, and each of both lateral sides of the tapered shape is formed to be inwardly parabolic.

6. The method of claim 2, wherein the etch mask comprises a pair of symmetrical tapered parts which extend in an axial direction, in which the pair of symmetrical tapered parts is configured such that inner lateral sides of the pair of symmetrical tapered parts, which face each other, linearly extend parallel to each other while outer lateral sides of the pair of symmetrical tapered parts are tapered.

7. A laterally graded porous silicon optical filter structure manufactured using a method of manufacturing a laterally graded porous silicon optical filter through diffusion-limited etching, the method comprising:

forming an etch mask; and

conducting anodic etching in a porous silicon etch bath.

8. The laterally graded porous silicon optical filter structure claim 7, wherein the etch mask has a tapered etch window opening, a width of which is gradually decreased from one end toward the other end along an axis of the tapered etch window opening.

9. The laterally graded porous silicon optical filter structure claim 8, wherein the tapered etch window opening includes a tapered shape, which extends in an axial direction thereof, such that the tapered etch window opening has a predetermined degree of taper between both ends thereof, and each of both lateral sides of the tapered shape is formed linearly.

10. The laterally graded porous silicon optical filter structure claim 8, wherein the tapered etch window opening has a tapered shape, which extends in an axial direction thereof, such that the tapered etch window opening has a predetermined degree of taper between both ends thereof, and each of both lateral sides of the tapered shape is formed to be outwardly parabolic.

11. The laterally graded porous silicon optical filter structure claim 8, wherein the tapered etch window opening has a tapered shape, which extends in an axial direction thereof, such that the tapered etch window opening has a predetermined degree of taper between both ends thereof, and each of both lateral sides of the tapered shape is formed to be inwardly parabolic.

12. The laterally graded porous silicon optical filter structure claim 8, wherein the etch mask comprises a pair of symmetrical tapered parts which extend in an axial direction, in which the pair of symmetrical tapered parts is configured such that inner lateral sides of the pair of symmetrical tapered parts, which face each other, linearly extend parallel to each other while outer lateral sides of the pair of symmetrical tapered parts are tapered.

13. A filter manufactured using the method of manufacturing a laterally graded porous silicon optical filter through diffusion-limited etching, the method comprising forming an etch mask, and conducting anodic etching in a porous silicon etch bath, the filter comprising:

distributed Bragg reflectors comprising eight layers having a thickness of λ

/4 and a central spacer layer disposed therebetween and having a thickness of λ

/2, and having a wavelength tuning range of 10˜

100 nm, a transmission bandwidth of 1˜

10 nm, and a center wavelength ranging from 400 nm to 2000 nm.

14. The filter of claim 13, wherein the etch mask has a tapered etch window opening, a width of which is gradually decreased from one end toward the other end along an axis of the tapered etch window opening.

15. The filter of claim 14, wherein the tapered etch window opening includes a tapered shape, which extends in an axial direction thereof, such that the tapered etch window opening has a predetermined degree of taper between both ends thereof, and each of both lateral sides of the tapered shape is formed linearly.

16. The filter of claim 14, wherein the tapered etch window opening has a tapered shape, which extends in an axial direction thereof, such that the tapered etch window opening has a predetermined degree of taper between both ends thereof, and each of both lateral sides of the tapered shape is formed to be outwardly parabolic.

17. The filter of claim 14, wherein the tapered etch window opening has a tapered shape, which extends in an axial direction thereof, such that the tapered etch window opening has a predetermined degree of taper between both ends thereof, and each of both lateral sides of the tapered shape is formed to be inwardly parabolic.

18. The filter of claim 14, wherein the etch mask comprises a pair of symmetrical tapered parts which extend in an axial direction, in which the pair of symmetrical tapered parts is configured such that inner lateral sides of the pair of symmetrical tapered parts, which face each other, linearly extend parallel to each other while outer lateral sides of the pair of symmetrical tapered parts are tapered.