Use of a cvd reactor for depositing two-dimensional layers

Patent metadata

Field	Value
Publication number	US-2023002905-A1
Application number	US-202017773512-A
Country	US
Kind code	A1
Filing date	Oct 30, 2020
Priority date	Nov 5, 2019
Publication date	Jan 5, 2023
Grant date	—

Abstract

A two-dimensional layer is deposited onto a substrate in a CVD reactor, in which a process gas is fed into a process chamber. The process gas in the process chamber is brought to the substrate, and the substrate is heated to a process temperature. After a chemical reaction of the process gas, the layer forms on the surface. During or after the heating of the substrate to the process temperature, the process gas with a first mass flow rate is initially fed into the process chamber and then, while the substrate surface is being observed, the mass flow rate of the process gas is increased to a rate at which the layer growth begins, and subsequently the mass flow rate of the process gas is increased by a predetermined value, during which the layer is deposited. The beginning of the layer growth is identified by observing measurements from a pyrometer.

First claim

1 . A method for depositing a two-dimensional layer onto a substrate in a chemical vapor deposition (CVD) reactor ( 1 ), the method comprising:
feeding process gas into a process chamber ( 3 ) via a gas inlet element ( 2 ) with gas outlet openings ( 14 , 24 ); bringing the process gas or its decomposition products into contact with a surface of the substrate ( 4 ) in the process chamber ( 3 ); and heating the substrate ( 4 ) to a process temperature (T P ) so that the two-dimensional layer is deposited onto the surface of the substrate ( 4 ) after a chemical reaction of the process gas, wherein feeding the process gas into the process chamber ( 3 ) comprises:
flowing the process gas with a first mass flow rate (Q 1 ) into the process chamber ( 3 ) while heating or after heating the substrate ( 4 ) to the process temperature (T P ), at which no layer growth takes place on the surface of the substrate ( 4 ),
after the substrate ( 4 ) has been heated to the process temperature (T P ), increasing the flow of the process gas to a second mass flow rate (Q 2 ) at which the layer growth on the surface of the substrate ( 4 ) starts to occur,
increasing the flow of the process gas to a third mass flow rate (Q 3 ) corresponding to a sum of the second mass flow rate (Q 2 ) with a prescribed value, and
maintaining the flow of the process gas at the third mass flow rate (Q) during which the two-dimensional layer is deposited.

2 . A chemical vapor deposition (CVD) reactor ( 1 ) for depositing a two-dimensional layer onto a substrate ( 4 ), the CVD reactor ( 1 ) comprising:
a process chamber ( 3 ); a gas inlet element ( 2 ) with gas outlet openings ( 14 , 24 ) that empty into the process chamber ( 3 ); a susceptor ( 5 ) for supporting the substrate ( 4 ); a heating device ( 6 ) for heating the substrate ( 4 ) to a process temperature (T P ); a feed line ( 10 ) for flowing a process gas into the gas inlet element ( 2 ) through the gas outlet openings ( 14 , 24 ) and into the process chamber ( 3 ); and a control device ( 29 ) configured to control one or more components of the CVD reactor ( 1 ) so as to:
flow the process gas with a first mass flow rate (Q 1 ) into the process chamber ( 3 ) while heating or after heating the substrate ( 4 ) to the process temperature (T P ), at which no layer growth takes place on a surface of the substrate ( 4 ),
after the substrate ( 4 ) has been heated to the process temperature T P ) increase the flow of the process to a second mass flow rate (Q 2 ) at which the layer growth on the surface of the substrate ( 4 ) starts to occur,
increase the flow of the process gas to a third mass flow rate (Q 3 ) corresponding to a sum of the second mass flow rate (Q 2 ) with a prescribed value, and
maintain the flow of the process gas at the third mass flow rate (Q) during which the two-dimensional layer is deposited on the surface of the substrate ( 4 ).

3 . The CVD reactor ( 1 ) of claim 2 , further comprising an optical device ( 19 ) for observing the surface of the substrate ( 4 ).

4 . The CVD reactor ( 1 ) of claim 3 , wherein the optical device ( 19 ) is a pyrometer.

5 . The method of claim 17 , wherein at least one of:
a starting time of the layer growth is determined by evaluating a measuring curve ( 26 ) recorded by the optical device ( 19 ), or the starting time of the layer growth is determined by detecting a change in a gradient of the measuring curve ( 26 ) recorded by the optical device ( 19 ).

6 . (canceled)

7 . The method of claim 5 , wherein the measuring curve ( 26 ) is used to determine a number of deposited layers.

8 . The method of claim 1 , wherein the prescribed value is at least 5 percent of the second mass flow rate (Q 2 ).

9 . The CVD apparatus ( 1 ) of claim 2 , further comprising:
a cooling chamber ( 8 ) through which a coolant flows; and a gas distribution volume ( 11 , 21 ), wherein the gas inlet element ( 2 ) has a gas outlet surface ( 25 ), which extends over a support surface ( 15 ) of the susceptor ( 5 ), wherein the gas outlet openings ( 14 , 24 ) are uniformly distributed over the gas outlet surface ( 25 ) and are fluidly connected with the gas distribution volume ( 11 , 21 ), wherein the gas outlet surface ( 25 ) comprises a gas outlet plate ( 9 ) of the gas inlet element ( 2 ), and wherein the gas outlet plate ( 9 ) is adjoined by the cooling chamber ( 8 ).

10 . (canceled)

11 . The CVD apparatus ( 1 ) of claim 9 ,
wherein a beam path ( 18 ) of the optical device ( 19 ) passes through the gas inlet element ( 2 ), and wherein a cover plate ( 16 ) of the gas inlet element ( 2 ) has (i) a window ( 17 ) that is transparent to a wavelength of radiation emitted by the optical device ( 19 ), and (ii) a tube ( 12 ′) through which the beam path ( 18 ) opens into the gas outlet surface ( 25 ).

12 . The method of claim 1 , wherein a distance between a support surface ( 15 ) of the susceptor ( 5 ) and a gas outlet surface ( 25 ) of the gas inlet element ( 2 ) is changed during the deposition of the two-dimensional layer.

13 . The method of claim 1 , wherein the process gas is generated by passing a carrier gas through a bubbler ( 32 , 32 ′) containing a solid or liquid starting material.

14 . The method of claim 13 , wherein a gas concentration measuring device ( 31 , 31 ′) downstream from the bubbler ( 32 , 32 ′) is used to determine a concentration of a vapor of the starting material in the carrier gas.

15 . The method of claim 17 , wherein the surface of the substrate ( 4 ) is further observed and the measuring curve ( 26 ) is further evaluated during layer deposition so as to switch off the process gas when a change in a gradient of a measuring curve ( 26 ) recorded by the optical device ( 19 ) is detected.

16 . (canceled)

17 . The method of claim 1 , wherein an optical device ( 19 ) is used to observe the surface of the substrate ( 4 ).

18 . The method of claim 17 , wherein the optical device ( 19 ) is a pyrometer.

19 . The method of claim 18 , wherein the pyrometer is a two-wavelength pyrometer.

20 . The method of claim 7 , wherein the number of deposited layers is determined by ascertaining a number of maximums or minimums present in the measuring curve ( 26 ).

21 . The CVD reactor ( 1 ) of claim 4 , wherein the pyrometer is a two-wavelength pyrometer.

22 . The CVD reactor ( 1 ) of claim 2 , further comprising a bubbler containing a solid or liquid starting material, wherein the process gas is generated by passing a carrier gas through the bubbler ( 32 , 32 ′).

23 . The CVD reactor ( 1 ) of claim 22 , further comprising a gas concentration measuring device ( 31 , 31 ′) disposed downstream from the bubbler ( 32 , 32 ′), wherein the gas concentration measuring device ( 31 , 31 ′) is configured to determine a concentration of a vapor of the starting material in the carrier gas.

Assignees

• Aixtron Se

Inventors

• Teo Kenneth B K
• Mcaleese Clifford
• Conran Ben Richard

Classifications

• C23C16/26

  Deposition of carbon only · CPC title

• C23C16/45557 Primary

  Pulsed pressure or control pressure · CPC title

• C23C16/45561

  Gas plumbing upstream of the reaction chamber · CPC title

• C23C16/4586

  Elements in the interior of the support, e.g. electrodes, heating or cooling devices · CPC title

• C23C16/4583

  the substrate being supported substantially horizontally · CPC title