Method and apparatus for controlled dopant incorporation and activation in a chemical vapor deposition system

Patent metadata

Field	Value
Publication number	US-9748113-B2
Application number	US-201514814153-A
Country	US
Kind code	B2
Filing date	Jul 30, 2015
Priority date	Jul 30, 2015
Publication date	Aug 29, 2017
Grant date	Aug 29, 2017

Abstract

Embodiments include systems and methods for producing semiconductor wafers having reduced quantities of point defects. These systems and methods include a tunable ultraviolet (UV) light source, which is controlled to produce a raster of a UV light beam across a surface of a semiconductor wafer during epitaxial growth to dissociate point defects in the semiconductor wafer. In various embodiments, the tunable UV light source is configured external to a Metal Organic Chemical Vapor Deposition (MOCVD) chamber and controlled such that the UV light beam is directed though a window defined in a wall of the MOCVD chamber.

First claim

What is claimed is:

1. A chemical vapor deposition system comprising:
a chemical vapor deposition reactor including:
a chamber;
a rotatable wafer carrier adapted to receive at least one wafer and rotate at a predetermined rotation speed during epitaxial growth;
at least one wafer mounted to the rotatable wafer carrier within the chamber;
a viewport defined in a wall of the chamber; and
a gas injection system configured to deliver a gas mixture towards the at least one wafer;
a UV light source configured to generate a UV light beam, the UV light source operably coupled to the viewport;
a rastering subsystem in communication with the UV light source and adapted to control the UV light beam through the viewport towards the at least one wafer to produce a raster pattern on a semiconductor layer formed on the at least one wafer mounted within chamber such that, during epitaxial growth, in response to the predetermined rotation speed the UV light beam is configured to be incident upon a plurality of regions of the semiconductor layer such that point defects in such regions are dissociated.

2. The chemical vapor deposition system of claim 1 , wherein the UV light source is selectively tuned to raise a quasi-Fermi level of the semiconductor layer and thereby dissociate point defects in the semiconductor layer without high temperature post-growth annealing of the semiconductor layer.

3. The chemical vapor deposition system of claim 1 , wherein the semiconductor layer includes an undoped or doped layer formed of a large bandgap material and wherein the UV light source is selectively tuned to alter a resistivity of the undoped or doped layer via modulation of point defect density.

4. The chemical vapor deposition system of claim 1 , wherein the UV light source is tuned to produce an energy level different than an energy level that affects either gas-phase reactions or surface atom chemical reactions of material grown on the semiconductor layer.

5. The chemical vapor deposition system of claim 1 , wherein the UV light beam is tuned to a wavelength suitable to excite specific bonds relating to group III organic compounds or intermediary adducts formed between the group III organic compounds and group V compounds.

6. The chemical vapor deposition system of claim 1 , wherein the raster pattern is dependent upon one or more of rotational speed of the one or more wafers, growth rate of deposited semiconductor layers and/or layout of the at least one wafer.

7. The chemical vapor deposition system of claim 1 , wherein the rastering system controls a flux of the UV light beam in response to the characteristics of the deposited layer(s).

8. The chemical vapor deposition system of claim 1 , wherein the UV light source includes an array of UV LED sources, at least some of which emit different wavelengths.

9. The chemical vapor deposition system of claim 1 , wherein the viewport is configured in a geometry allowing full optical access to image the entire surface of the semiconductor layer.

10. The chemical vapor deposition system of claim 1 , wherein the window is made of optically UV transparent material.

11. The chemical vapor deposition system of claim 1 , wherein the at least one wafer comprises at least one epitaxially grown semiconductor layer.

12. A semiconductor processing system configured for epitaxial growth of one or more device layers on at least one wafer, the system comprising:
a single vacuum chamber comprising a plurality of processing chambers, each of the plurality of processing chambers having a top portion and a bottom portion, the single vacuum chamber having:
a cover containing the top portion of each of the plurality of processing chambers, each top portion having at least a gas injection system configured to deliver a gas mixture, and at least one of metrology instruments, thermal and other non-deposition treating systems, and testing systems, a viewport defined in the cover, and a UV light source configured to generate a UV light beam, the UV light source operably coupled to the viewport and in communication with a rastering subsystem; and
a base comprising a carousel rotatably mounted within the base, the carousel containing the bottom portion of each of the plurality of processing chambers, each bottom portion adapted to receive at least one wafer rotatably mounted therein and rotate at a predetermined rotation speed during epitaxial growth from the gas mixture, wherein when the top portion and the bottom portion of each of the plurality of processing chambers are engaged by closing the cover on the base, each of the plurality of processing chambers are sealed off from each other processing chamber, and wherein the rastering subsystem is in communication with the UV light source and adapted to control the UV light beam through the viewport towards the at least one wafer during epitaxial growth to produce a raster pattern on a semiconductor layer formed on the at least one wafer mounted within chamber in response to the predetermined rotation speed such that the UV light beam is configured to be incident upon a plurality of regions of the semiconductor layer such that point defects in such regions are dissociated.

13. A method for epitaxial growth of at least one semiconductor layer comprising:
positioning at least one wafer within a chamber defined within a chemical vapor deposition reactor, the chemical vapor deposition system comprising:
a rotatable wafer carrier adapted to receive the at least one wafer;
a viewport defined in a wall of the chamber; a gas injection system configured to deliver a gas mixture towards the at least one wafer:
a UV light source configured to generate a UV light beam, the UV light source operably coupled to the viewport: and
a rastering subsystem in communication with the UV light source and adapted to control the UV light beam through the viewport towards the at least one wafer: and rotating the rotatable wafer carrier at a predetermined rotation speed during epitaxial growth of the at least one wafer;
applying a gas mixture within the chamber to cause the at least one semiconductor layer to grow epitaxially on the at least one wafer; and selectively directing a UV light beam through a rastering system to produce a raster pattern on the at least one semiconductor layer, the UV light beam selectively tuned to the at least one semiconductor layer and the gas mixture during the rotating of the rotatable wafer carrier and in response to the predetermined rotation speed such that the UV light beam is configured to be incident upon a plurality of regions of the semiconductor layer so as to dissociate point defects in the at least one semiconductor layer.

14. The method of claim 13 further comprising tuning the UV beam to raise a quasi-Fermi level of the at least one semiconductor layer and thereby dissociate point defects in the at least one semiconductor layer without high temperature post-growth annealing of the least one semiconductor layer.

15. The method of claim 13 , wherein the at least one semiconductor layer includes an undoped or doped layer formed of a large bandgap material, and wherein the UV light beam is selectively tuned to alter a resistivity of the undoped or doped layer via modulation of point defect density.

16. The method of claim 13 , wherein the UV light beam is tuned to produce an energy level different than an energy level that affects either gas-phase reactions or surface atom chemical reactions of the material grown on the at least one semiconductor layer.

17. The method of claim 13 , further comprising tuning the

Assignees

• Veeco Instr Inc
• Veeco Intruments Inc

Inventors

• Armour Eric
• Papasouliotis George
• Kwon Daewon

Classifications

• H10P14/3416

  Nitrides · CPC title

• H10P14/24

  using chemical vapour deposition [CVD] · CPC title

• H10P95/904 Primary

  of Group III-V semiconductors · CPC title

• H01L33/0075

  Electricity · mapped topic

• H01L29/205

  Electricity · mapped topic