ATOMIC LAYER ETCHING OF GaN AND OTHER III-V MATERIALS

Patent metadata

Field	Value
Publication number	US-2016358782-A1
Application number	US-201615173358-A
Country	US
Kind code	A1
Filing date	Jun 3, 2016
Priority date	Jun 5, 2015
Publication date	Dec 8, 2016
Grant date	—

Abstract

Provided herein are ALE methods of removing III-V materials such as gallium nitride (GaN) and related apparatus. In some embodiments, the methods involve exposing the III-V material to a chlorine-containing plasma without biasing the substrate to form a modified III-V surface layer; and applying a bias voltage to the substrate while exposing the modified III-V surface layer to a plasma to thereby remove the modified III-V surface layer. The disclosed methods are suitable for a wide range of applications, including etching processes for trenches and holes, fabrication of HEMTs, fabrication of LEDs, and improved selectivity in etching processes.

First claim

What is claimed is:

1 . A method of etching a III-V material on a substrate, comprising:
a) exposing the III-V material to a chlorine-containing plasma without biasing the substrate to form a modified III-V surface layer; and b) applying a bias voltage to the substrate while exposing the modified III-V surface layer to an inert plasma to thereby remove the modified III-V surface layer.

2 . The method of claim 1 , further comprising repeating (a) and (b) one or more times.

3 . The method of claim 1 , wherein the bias voltage is at a level such that the removal is in a self-limiting regime.

4 . The method of claim 1 , wherein the chlorine-containing plasma is generated from a process gas including a boron-containing compound, wherein about 0.5% to 10% (volumetric) of the process gas is the boron-containing compound.

5 . The method of claim 1 , further comprising performing one or more additional cycles of (a) and (b), wherein the bias voltage is lowered during the one or more additional cycles.

6 . The method of claim 1 , wherein the III-V material is GaN. The method of claim 6 , wherein GaN is removed without removing an underlayer.

8 . The method of claim 7 , wherein the underlayer is AlGaN.

9 . The method of claim 1 , wherein the bias voltage is between about 20 V and 120 V.

10 . The method of claim 1 , wherein the bias voltage is between about 50 V and 120 V.

11 . The method of claim 1 , wherein the bias voltage is between about 50 V and 100 V.

12 . The method of claim 1 , wherein the chlorine-containing plasma is generated from a mixture of a chlorine-containing gas and a boron-containing gas.

13 . The method of claim 1 , wherein the chlorine-containing plasma is generated from a mixture of a Cl 2 and BCl 3 .

14 . The method of claim 1 , wherein the inert plasma in (b) is an argon-containing plasma.

15 . The method of claim 1 , wherein the bias voltage is at level such that the etch is selective to an underlying material.

16 . An apparatus for processing semiconductor substrates, the apparatus comprising:
a process chamber comprising a substrate support; a power supply connected to the substrate support; a plasma generator; and a controller having at least one processor and a memory,
wherein the at least one processor and the memory are communicatively connected with one another, and
the memory stores machine-readable instructions for:
(i) introducing a chlorine-containing gas to the plasma generator;
(ii) igniting a chlorine-containing plasma in the plasma generator;
(iii) exposing a substrate to the chlorine-containing plasma to modify a III-V layer on the substrate without biasing the substrate;
(iv) introducing an inert gas to the plasma generator;
(v) igniting an inert plasma in the plasma generator; and
(vi) using the power supply to apply a bias voltage to the substrate while exposing the substrate to the inert plasma to remove the modified layer.

Assignees

• Lam Res Corp

Inventors

• Yang Wenbing
• Ohba Tomihito
• Tan Samantha
• Kanarik Keren Jacobs
• Marks Jeffrey
• Nojiri Kazuo

Classifications

• H10P72/0468

  comprising a chamber adapted to a particular process · CPC title

• H10P50/246 Primary

  of Group III-V materials · CPC title

• H10P50/20

  Dry etching; Plasma etching; Reactive-ion etching · CPC title

• H10P50/242 Primary

  of Group IV materials · CPC title

• H10D62/8503

  Nitride Group III-V materials, e.g. AlN or GaN · CPC title