Crystallization processing for semiconductor applications

• US 9,455,145 B2
• Filed: 02/05/2016
• Issued: 09/27/2016
• Est. Priority Date: 11/30/2009
• Status: Active Grant

• Current Assignee: Applied Materials Incorporated
• Original Assignee: Applied Materials Incorporated
• Inventors: Moffatt, Stephen
• Primary Examiner(s): SHOOK, DANIEL P
• Application Number:
  US15/016,328
• Publication Number:
  US 20160155638A1
• Time in Patent Office: 235 Days
• Field of Search: 117/44, 257/E21.347, 438/36, 438/89, 438/166, 438/797, 438/799
• US Class Current: 1/1
• CPC Class Codes: C30B 13/24 using electromagnetic waves
• CPC Class Codes: C30B 29/403 AIII-nitrides
• CPC Class Codes: H01L 21/02532 Silicon, silicon germanium, germanium
• CPC Class Codes: H01L 21/02568 Chalcogenide semiconducting materials not being oxides, e.g. ternary compounds
• CPC Class Codes: H01L 21/02686 Pulsed laser beam
• CPC Class Codes: H01L 21/2636 for heating, e.g. electron beam heating
• CPC Class Codes: H01L 21/268 using electromagnetic radiation, e.g. laser radiation
• CPC Class Codes: H01L 29/685 Hi-Lo semiconductor devices, e.g. memory devices
• CPC Class Codes: H01L 31/1872 Recrystallisation
• CPC Class Codes: H01L 33/0095 Post-treatment of devices, e.g. annealing, recrystallisation or short-circuit elimination
• CPC Class Codes: Y02E 10/50 Photovoltaic [PV] energy
• CPC Class Codes: Y02E 10/547 Monocrystalline silicon PV cells
• CPC Class Codes: Y02E 10/548 Amorphous silicon PV cells
• CPC Class Codes: Y02P 70/50 Manufacturing or production processes characterised by the final manufactured product

Abstract

A method and apparatus for forming a crystalline semiconductor layer on a substrate are provided. A semiconductor layer is formed by vapor deposition. A pulsed laser melt/recrystallization process is performed to convert the semiconductor layer to a crystalline layer. Laser, or other electromagnetic radiation, pulses are formed into a pulse train and uniformly distributed over a treatment zone, and successive neighboring treatment zones are exposed to the pulse train to progressively convert the deposited material to crystalline material.

Claims

1. A method, comprising:

forming a semiconductor layer on a crystalline substrate;

melting a portion of the semiconductor layer by exposing the semiconductor layer to a plurality of energy pulses, wherein the plurality of energy pulses melts the portion of the semiconductor layer to reach a melt end point a distance from an interface between the semiconductor layer and the crystalline substrate, wherein a buffer layer is defined between the melt end point and the interface;

crystallizing the buffer layer by exposing the semiconductor layer to a first group of one or more energy pulses distinct from the plurality of energy pulses, wherein a crystal structure of the buffer layer is formed; and

crystallizing the melted portion of the semiconductor layer by the first group of one or more energy pulses, wherein a crystal structure of the melted portion of the semiconductor layer is developed from the crystal structure of the buffer layer.

2. The method of claim 1, wherein the plurality of energy pulses includes a second group of one or more energy pulses and a third group of one or more energy pulses.

3. The method of claim 2, wherein a power delivered by the third group of one or more energy pulses is higher than a power delivered by the second group of one or more energy pulses.

4. The method of claim 2, wherein a power delivered by the first group of one or more energy pulses is less than a power delivered by the second group of one or more energy pulses.

5. The method of claim 2, wherein the second group of one or more energy pulses is separated from the third group of one or more energy pulses by a rest duration.

6. The method of claim 5, wherein the rest duration allows partial refreezing of the melted portion of the semiconductor layer.

7. The method of claim 1, wherein the semiconductor layer is doped.

8. A method of treating a substrate, comprising:

forming a semiconductor layer on a crystalline substrate;

identifying a first treatment zone on the semiconductor layer;

melting a portion of the semiconductor layer by exposing the first treatment zone of the semiconductor layer to a plurality of energy pulses, wherein the plurality of energy pulses melts the portion of the semiconductor layer to reach a melt end point a distance from an interface between the semiconductor layer and the crystalline substrate, wherein a buffer layer is defined between the melt end point and the interface;

crystallizing a portion of the buffer layer by exposing the first treatment zone of the semiconductor layer to a first group of one or more energy pulses distinct from the plurality of energy pulses, wherein a crystal structure of the portion of the buffer layer is formed;

crystallizing the melted portion of the first treatment zone of the semiconductor layer by the first group of one or more energy pulses, wherein a crystal structure of the melted portion of the semiconductor layer is developed from the crystal structure of the portion of the buffer layer;

identifying a second treatment zone; and

repeating melting a portion of the semiconductor layer, crystallizing a portion of the buffer layer and crystallizing the melted portion of the second treatment zone.

9. The method of claim 8, wherein the plurality of energy pulses includes a second group of one or more energy pulses and a third group of one or more energy pulses.

10. The method of claim 9, wherein a power delivered by the third group of one or more energy pulses is higher than a power delivered by the second group of one or more energy pulses.

11. The method of claim 9, wherein a power delivered by the first group of one or more energy pulses is less than a power delivered by the third group of one or more energy pulses.

12. The method of claim 9, wherein a power delivered by the first group of one or more energy pulses is less than a power delivered by the second group of one or more energy pulses.

13. The method of claim 9, wherein the second group of one or more energy pulses is separated from the third group of one or more energy pulses by a rest duration.

14. The method of claim 13, wherein the rest duration allows partial refreezing of the melted portion of the semiconductor layer.

15. A method, comprising:

forming a semiconductor layer on a crystalline substrate;

melting a portion of the semiconductor layer by exposing the semiconductor layer to a plurality of energy pulses, wherein the plurality of energy pulses melts the portion of the semiconductor layer to reach a melt end point a distance from an interface between the semiconductor layer and the crystalline substrate, wherein the plurality of energy pulses includes a first energy pulse at a first intensity and a first group of one or more energy pulses at a second intensity greater than the first intensity, wherein a buffer layer is defined between the melt end point and the interface;

crystallizing the buffer layer by exposing the semiconductor layer to a second group of one or more energy pulses distinct from the plurality of energy pulses, wherein a crystal structure of the buffer layer is formed; and

crystallizing the melted portion of the semiconductor layer by the first group of one or more energy pulses, wherein a crystal structure of the melted portion of the semiconductor layer is developed from the crystal structure of the buffer layer.

16. The method of claim 15, wherein the second group of one or more energy pulses each has a third intensity less than the second intensity.

17. The method of claim 15, wherein the second group of one or more energy pulses each has a third intensity less than the first intensity.

18. The method of claim 15, wherein the first energy pulse is separated from the first group of one or more energy pulses by a rest duration.

19. The method of claim 18, wherein the rest duration allows partial refreezing of the melted portion of the semiconductor layer.

20. The method of claim 15, wherein the first group of one or more energy pulses includes 10 energy pulses.