Process for the manufacture of a doped III-N bulk crystal and a free-standing III-N substrate, and doped III-N bulk crystal and free-standing III-N substrate as such

• US 9,461,121 B2
• Filed: 02/05/2014
• Issued: 10/04/2016
• Est. Priority Date: 08/09/2006
• Status: Active Grant

• Current Assignee: Freiberger Compound Materials GMBH (Federmann House Limited)
• Original Assignee: Freiberger Compound Materials GMBH (Federmann House Limited)
• Inventors: Brckner, Peter, Scholz, Ferdinand, Habel, Frank, Leibiger, Gunnar
• Primary Examiner(s): SONG, MATTHEW J
• Application Number:
  US14/173,336
• Publication Number:
  US 20140151716A1
• Time in Patent Office: 972 Days
• Field of Search: 428/698, 257/103, 117/952
• US Class Current: 1/1
• CPC Class Codes: C30B 25/00 Single-crystal growth by chemical reaction of reactive gases, e.g. chemical vapour-deposition growth
• CPC Class Codes: C30B 25/02 Epitaxial-layer growth
• CPC Class Codes: C30B 25/165 the flow of the reactive gases
• CPC Class Codes: C30B 29/403 AIII-nitrides
• CPC Class Codes: C30B 29/406 Gallium nitride
• CPC Class Codes: H01L 21/0254 Nitrides
• CPC Class Codes: H01L 29/2003 Nitride compounds

Abstract

A process for producing a doped III-N bulk crystal, wherein III denotes at least one element of the main group III of the periodic system, selected from Al, Ga and In, wherein the doped crystalline III-N layer or the doped III-N bulk crystal is deposited on a substrate or template in a reactor, and wherein the feeding of at least one dopant into the reactor is carried out in admixture with at least one group III material. In this manner, III-N bulk crystals and III-N single crystal substrates separated therefrom can be obtained with a very homogeneous distribution of dopants in the growth direction as well as in the growth plane perpendicular thereto, a very homogeneous distribution of charge carriers and/or of the specific electric resistivity in the growth direction as well as in the growth plane perpendicular thereto, and a very good crystal quality.

Claims

1. A doped, epitaxially grown III-N bulk crystal, wherein III denotes at least one element of the main group III of the periodic system selected from Al, Ga and In, wherein the doped III-N bulk crystal satisfies at least one of the following conditions (a) to (c):

(a) in a micro-Raman mapping on a plane

(i) parallel to a growth plane and/or

(ii) in a growth direction

a standard deviation of the measured frequency positions of the LPP⁺-mode

in case of (i) is 5% or lower, and

in case of (ii) is 10% or lower;

(b) in an MDP mapping on a plane

(i) parallel to a growth plane and/or

(ii) in a growth direction

a standard deviation of the photoconductivity signals

in case of (i) is 5% or lower, and

in case of (ii) is 10% or lower;

(c) in a micro photoluminescence mapping on a plane

(i) parallel to a growth plane and/or

(ii) in a growth direction

a standard deviation of the line width of the D⁰X transition

in case of (i) is 5% or lower, and

in case of (ii) is 10% or lower.

2. The doped, epitaxially grown III-N bulk crystal according to claim 1, wherein in a micro-Raman mapping on a plane

(i) parallel to a growth plane and/or

(ii) in a growth direction

a standard deviation of the measured half-widths of the E₂-phonon

in case of (i) is 5% or lower, and

in case of (ii) is 5% or lower.

3. The doped, epitaxially grown III-N bulk crystal according to claim 1, wherein the doped III-N bulk crystal has a circular or almost circular cross-section, and the diameter of the III-N bulk crystal is ≧

0.5 cm.

4. The doped, epitaxially grown III-N bulk crystal according to claim 1, wherein the length of the doped, epitaxially grown III-N bulk crystal is ≧

0.1 mm.

5. The doped, epitaxially grown III-N bulk crystal according to claim 1, wherein the length of the doped, epitaxially grown III-N bulk crystal is ≧

1 mm.

6. The doped, epitaxially grown III-N bulk crystal according to claim 1, wherein the length of the doped, epitaxially grown III-N bulk crystal is ≧

1 cm.

7. The doped III-N bulk crystal according to claim 1, wherein the length of the doped, epitaxially grown III-N bulk crystal is ≧

3 cm.

8. The doped, epitaxially grown III-N bulk crystal according to claim 1, wherein the doped III-N bulk crystal is grown by epitaxy above a foreign substrate selected from the group consisting of sapphire, silicon carbide, gallium arsenide, lithium aluminate and silicon.

9. The doped, epitaxially grown III-N bulk crystal according to claim 1, wherein the doped III-N bulk crystal is grown by epitaxy on a doped or undoped GaN substrate as a substrate, or on a foreign substrate having GaN deposited on a foreign substrate.

10. The doped, epitaxially grown III-N bulk crystal according to claim 1, wherein the doped III-N bulk crystal is grown by epitaxy comprising a mixed feeding from a common source material in which at least one dopant has been added to the at least one group III starting material.

11. The doped, epitaxially grown III-N bulk crystal according to claim 10, wherein the common source material comprises at least one dopant in elemental form and the at least one group III starting material in elemental form.

12. The doped, epitaxially grown III-N bulk crystal according to claim 10, wherein the common source material is in the form of a solid solution, an alloy or a mixed melt of the at least one dopant and the at least one group III starting material.

13. The doped, epitaxially grown III-N bulk crystal according to claim 1, wherein the doped III-N bulk crystal is grown by hydride vapor phase epitaxy.

14. The doped, epitaxially grown III-N bulk crystal according to claim 1, wherein the dopant is selected from the group consisting of silicon, tellurium, magnesium, iron, germanium, tin, selenium, beryllium, vanadium, manganese, zinc, chrome, nickel, copper and a mixture thereof.

15. A free-standing doped III-N substrate, wherein III denotes at least one element of the main group III of the periodic system selected from Al, Ga and In,

wherein the free-standing doped III-N substrate satisfies at least one of the following conditions (a) to (c):

(a) in a micro-Raman mapping on a plane

(i) parallel to a growth plane and/or

(ii) in a growth direction

a standard deviation of the measured frequency positions of the LPP⁺-mode

in case of (i) is 5% or lower, and

in case of (ii) is 5% or lower;

(b) in an MDP mapping on a plane

(i) parallel to a growth plane and/or

(ii) in a growth direction

a standard deviation of the photoconductivity signals

in case of (i) is 5% or lower, and

in case of (ii) is 5% or lower;

(c) in a micro photoluminescence mapping on a plane

(i) parallel to a growth plane and/or

(ii) in a growth direction

a standard deviation of the line width of the D°

X transition

in case of (i) is 5% or lower, and

in case of (ii) is 5% or lower.

16. The free-standing doped III-N substrate according to claim 15, wherein in a micro-Raman mapping on a plane

(i) parallel to a growth plane and/or

(ii) in a growth direction

a standard deviation of the measured half-widths of the E₂-phonon

in case of (i) is 5% or lower, and

in case of (ii) is 5% or lower.

17. The free-standing doped III-N substrate according to claim 15, which has a circular or almost circular cross-section, and the diameter of the substrate is ≧

5 cm.

18. The free-standing doped III-N substrate according to claim 15, which has been separated from a doped, epitaxially grown III-N bulk crystal, wherein the doped III-N bulk crystal satisfies at least one of the following conditions (d) to (f):

(d) in a micro-Raman mapping on a plane

(i) parallel to a growth plane and/or

(ii) in a growth direction

a standard deviation of the measured frequency positions of the LPP⁺-mode

in case of (i) is 5% or lower, and

in case of (ii) is 10% or lower;

(e) in an MDP mapping on a plane

(i) parallel to a growth plane and/or

(ii) in a growth direction

a standard deviation of the photoconductivity signals

in case of (i) is 5% or lower, and

in case of (ii) is 10% or lower;

(f) in a micro photoluminescence mapping on a plane

(i) parallel to a growth plane and/or

(ii) in a growth direction

a standard deviation of the line width of the D°

X transition

in case of (i) is 5% or lower, and

in case of (ii) is 10% or lower.