Nitride substrate of a Group III element and a method for producing a nitride substrate of a Group III element
By controlling the elastic modulus variation in Group III element nitride substrates through varied growth rates and base removal, deformation is suppressed, enhancing substrate uniformity and workability for functional layer formation.
Patent Information
- Application Number
- DE112022007904
- Authority / Receiving Office
- DE · DE
- Patent Type
- Applications
- Current Assignee / Owner
- Filing Date
- 2022-12-13
- Publication Date
- 2025-07-31
AI Technical Summary
Group III element nitride substrates obtained through heteroepitaxial growth are prone to deformation due to mismatched lattice constants and thermal expansion coefficients between the base substrate and the nitride crystal.
A Group III element nitride substrate with controlled elastic modulus variation in the thickness direction, achieved by varying the growth rate of the nitride crystal and removing the base substrate to form a free-standing substrate, ensuring the elastic modulus variation is within specific limits.
The solution effectively suppresses deformation in the nitride substrate, allowing for improved uniformity and workability in forming functional layers, particularly for large-sized devices.
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Abstract
Claims
[1] A Group III element nitride substrate comprising a first main surface and a second main surface opposite to each other, wherein the variation range of the elastic modulus in the thickness direction of the Group III element nitride substrate is 50% or less. [2] The Group III element nitride substrate according to claim 1, wherein the Group III element nitride substrate is a freestanding substrate of a Group III element nitride crystal. [3] The Group III element nitride substrate according to claim 1, wherein the Group III element nitride substrate has a thickness of 250 µm or more and 800 µm or less. [4] The Group III element nitride substrate according to claim 1, wherein the variation range of the elastic modulus in the thickness direction is 35% or less. [5] The Group III element nitride substrate according to claim 1, wherein the variation range of the elastic modulus in the thickness direction is 1% or more. [6] The Group III element nitride substrate according to claim 1, wherein the elastic modulus increases from a second main surface side to a first main surface side. [7] The Group III element nitride substrate according to claim 1, wherein the absolute value of the difference between the elastic modulus in the first main surface and the elastic modulus in the second main surface is 100 GPa or less. [8] The Group III element nitride substrate according to claim 1, wherein the thickness direction is substantially a c-axis direction of a Group III element nitride crystal. [9] The Group III element nitride substrate according to claim 1, wherein the elastic modulus is measured by a nanoindentation method. [10] A method for producing the Group III element nitride substrate according to any one of claims 1 to 9, the method comprising: Producing a seed crystal substrate including a base substrate having an upper surface and a lower surface opposite to each other, and a seed crystal film to be formed on the upper surface of the base substrate; Growing a nitride crystal of a Group III element on the seed crystal film of the seed crystal substrate; and Removing the base substrate from the nitride crystal of a group III element, wherein the growth of the nitride crystal of a group III element is carried out by changing the growth rate of the nitride crystal of a group III element. [11] The manufacturing method according to claim 10, wherein the base substrate contains a material different in composition from the nitride crystal of a Group III element.
Citation Information
Patent Citations
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JP2005136167A
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JP5244628B2