Substrate with refractive index matching

• US 20060197096A1
• Filed: 04/25/2006
• Published: 09/07/2006
• Est. Priority Date: 10/30/2003
• Status: Abandoned Application

• Current Assignee: Soitec Silicon On Insulator Technologies SA (Soitec S.A.)
• Original Assignee: Soitec Silicon On Insulator Technologies SA (Soitec S.A.)
• Inventors: Kerdiles, Sebastien, Le Vaillant, Yves-Mathieu
• Application Number:
  US11/412,215
• Publication Number:
  US 20060197096A1
• Time in Patent Office: Days
• US Class Current: 257/79
• CPC Class Codes: G02B 1/113 using inorganic layer materials only
• CPC Class Codes: H01L 2924/00 Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
• CPC Class Codes: H01L 2924/0002 Not covered by any one of groups H01L24/00, H01L24/00 and H01L2224/00
• CPC Class Codes: H01L 31/0216 Coatings H01L31/041 takes precedence
• CPC Class Codes: H01L 31/02168 the coatings being antireflective or having enhancing optical properties for the solar cells
• CPC Class Codes: H01L 31/0392 including thin films deposited on metallic or insulating substrates ; characterised by specific substrate materials or substrate features or by the presence of intermediate layers, e.g. barrier layers, on the substrate textured substrates H01L31/02366
• CPC Class Codes: H01L 31/1892 methods involving the use of temporary, removable substrates
• CPC Class Codes: H01L 33/44 characterised by the coatings, e.g. passivation layer or anti-reflective coating
• CPC Class Codes: Y02E 10/50 Photovoltaic [PV] energy

Abstract

This invention provides a composite substrate that has a transparent mechanical support, for example of glass or quartz, a film or thin layer of monocrystalline semi-conductive material and an intermediate antireflective layer located between the thin layer or the semi-conductive film and the support. The composition of the intermediate antireflective layer varies between the support and the semi-conductive film, so that the refractive index similarly varies.

Claims

1. A composite semiconductor substrate comprising:

a transparent support;

a film of semi-conductive material; and

at least one antireflective layer between the transparent support and the semi-conductive film, the antireflective layer having a varying index of refraction that depends at least in part on a varying composition of the antireflective layer.

2. The substrate according to claim 1, in which the semi-conductive material comprises Si, Ge, SiGe, SiC, GaAs, GaP, InP, AlGaInP, GaN, AlN, AlGaN, InGaN, and AlGaInN.

3. The substrate according to claim 1, in which the antireflective layer comprises an oxide, nitride, carbide, or a mixture of oxide and nitride.

4. The substrate according to claim 3, in which the antireflective layer comprises silicon oxide, silicon nitride, silicon carbide, silicon oxynitride (SiO_xN_y), SiC_xN_y, gallium nitride, or aluminum nitride.

5. The substrate according to claim 1, in which the antireflective layer comprises a plurality of stacked sub-layers, with each sub-layer having a refractive index, ni, close to a value determined by the relation (ni+1×

ni−

1)ˆ

(½

), in which ni+1, ni−

1 are the refractive indices of materials on either side of the sub-layer in question.

6. The substrate according to claim 1, in which the antireflective layer comprises SiO₂ in contact with the support, then silicon oxynitride SiO_xN_y with a proportion of nitrogen that is increased until Si₃N₄ is formed close to the semi-conductive layer.

7. The substrate according to claim 1, in which the antireflective layer comprises Si₃N₄ in contact with the support, then SiC_xN_y with a proportion of nitrogen that is reduced and a proportion of carbon that is increased until SiC is formed close to the semi-conductive layer.

8. The substrate according to claim 1, in which the antireflective layer comprises SiO2 in contact with the support, then SiOxNy with a proportion of nitrogen that is reduced and a proportion of carbon that is increased until SiC is formed close to the semi-conductive layer.

9. The substrate according to claim 1, in which the antireflective layer is an electrical insulator.

10. The substrate according to claim 1, in which the transparent support comprises glass or quartz and the semi-conductive material comprises gallium arsenide (GaAs).

11. The substrate according to claim 1, in which the transparent support comprises glass or quartz and the semi-conductive material comprises silicon (Si).

12. A light emitting or receiving device comprising:

a composite semiconductor substrate according to claim 1;

and

light emitting or detecting means at least partially formed in or on the film of semi-conductive material.

13. A method of producing a composite semiconductor substrate comprising:

producing at least an antireflective layer with a varying index of refraction on a transparent support, the varying index of refraction depending at least in part on a varying composition of the antireflective layer;

assembling the transparent support and a substrate of semi-conductive material so that the antireflective layer is between the transparent support and the semi-conductive substrate; and

thinning the substrate of semi-conductive material to form the composite semiconductor substrate.

14. The method according to claim 13, in which the assembling the transparent support and the semi-conductive substrate comprises molecular bonding.

15. The method according to claim 13, in which the thinning of the semi-conductive substrate comprises producing a layer or zone of weakness and splitting the substrate at or in the zone of weakness.

16. The method according to claim 15, in which the layer or zone of weakness comprises a layer of porous silicon.

17. The method according to claim 15, in which producing the layer or zone of weakness comprises ion implantation in the second semiconductor substrate.

18. The method according to claim 17, in which the implanted ions are hydrogen ions, or a co-implantation of hydrogen ions and helium ions.

19. The method according to claim 13, in which thinning of the semi-conductive substrate comprises polishing or etching.

20. The method according to claim 13, in which the transparent support comprises glass or quartz or a semi-conductive material.

21. The method according to claim 13, wherein the thin antireflective layer is produced to comprise Si₃N₄ in contact with the support, then SiC_xN_y with a proportion of nitrogen that is reduced and a proportion of carbon that is increased until SiC is formed close to the semi-conductive layer.

22. The method according to claim 13, wherein the thin antireflective layer is produced to comprise SiO2 in contact with the support, then SiO_xN_y with a proportion of nitrogen that is continuously reduced and a proportion of carbon that is continuously increased until SiC is formed close to the semi-conductive layer.