Epitaxial formation structures and associated methods of manufacturing solid state lighting devices
Epitaxial formation structures and associated methods of manufacturing solid state lighting (“SSL”) devices with target thermal expansion characteristics are disclosed herein. In one embodiment, an SSL device includes a composite structure having a composite CTE temperature dependency, a formation structure on the composite structure, and an SSL structure on the formation structure. The SSL structure has an SSL temperature dependency, and a difference between the composite CTE and SSL temperature dependencies is below 3 ppm/° C. over the temperature range.
1. A method for manufacturing a solid state lighting (SSL) device, comprising:
attaching a formation structure to a composite structure, the composite structure having a composite coefficient of thermal expansion (CTE) dependency over a temperature range, the composite structure containing a base material and a CTE control material contained within the base material, the base material including a single crystalline material or a polycrystalline material; and
reducing a thickness of the formation structure attached to the composite structure;
forming an SSL structure on the formation structure with the reduced thickness, the SSL structure having an SSL CTE temperature dependency over the temperature range,
wherein a difference between the composite and SSL CTE temperature dependencies is below a target threshold over at least a portion of the temperature range,
and wherein
the base material of the composite structure contains polycrystalline aluminum nitride (AlN) and the CTE control material of the composite structure contains yttrium oxide (Y 2 O 3 ), and
a volume ratio of the base material to the CTE control material is between about 0.75 to about 0.95.
2. The method of claim 1 wherein:
the formation structure includes an Si(1,1,1) silicon wafer;
the CTE control material of the composite structure further contains at least one of silicon nitride (Si 3 N 4 ), titanium nitride (TiN), zirconium nitride (ZrN), hafnium nitride (HfN), silicon oxide (SiO 2 ), aluminum oxide (Al 2 O 3 ), aluminum oxynitride (AlON), titanium carbide (TiC), zirconium carbide (ZrC), hafnium carbide (HfC), silicon carbide (SiC);
attaching the formation structure includes attaching the Si(1,1,1) silicon wafer to the composite structure through solid-solid bonding;
reducing the thickness of the formation structure includes implanting a dopant in the formation structure and exfoliating the dopant after the formation structure is attached to the composite structure;
the reduced thickness of the formation structure is about 10 nanometers to about 2 micrometers;
forming the SSL structure includes forming a first semiconductor material, an active region, and a second semiconductor material on the formation structure with the reduced thickness;
the first semiconductor material contains N-type gallium nitride (GaN);
the second semiconductor material contains P-type GaN;
the active region includes at least one of a bulk indium gallium nitride (InGaN), an InGaN single quantum well, and GaN/InGaN multiple quantum wells;
the difference between the composite and SSL CTE temperature dependencies is below a target threshold over the entire temperature range; and
the target threshold is between about 1 ppm/° C. and 3 ppm/° C.
3. The method of claim 1 wherein the difference between the composite and SSL CTE temperature dependencies is below the target threshold over the entire temperature range.
4. The method of claim 1 wherein the difference between the composite and SSL CTE temperature dependencies is between about 1 ppm/° C. and 3 ppm/° C. over the entire temperature range.
5. The method of claim 1 wherein an integrated difference between the composite and SSL CTE temperature dependencies over the temperature range is below the target threshold.
6. The method of claim 1 wherein:
the CTE control material of the composite structure further contains at least one of silicon nitride (Si 3 N 4 ), titanium nitride (TiN), zirconium nitride (ZrN), hafnium nitride (HfN), silicon oxide (SiO 2 ), aluminum oxide (Al 2 O 3 ), aluminum oxynitride (AlON), titanium carbide (TiC), zirconium carbide (ZrC), hafnium carbide (HfC), silicon carbide (SiC); and
the base material and the CTE control material have a volume ratio such that the difference between the composite and SSL CTE temperature dependencies is below the target threshold.
7. The method of claim 1 wherein the base material and the CTE control material have a volume ratio such that the difference between the composite and SSL CTE temperature dependencies is below the target threshold.
8. The method of claim 1 wherein:
the CTE control material includes a first CTE control material and a second CTE control material;
the temperature range includes a first temperature range and a second temperature range;
the composite structure has a first temperature dependency in the first temperature range corresponding to the first CTE control material;
the composite structure has a second temperature dependency in the second temperature range corresponding to the second CTE control material;
a first difference between the first CTE temperature dependency and the SSL temperature dependency is below the target threshold; and
a second difference between the second CTE temperature dependency and the SSL temperature dependency is also below the target threshold.
9. A method for manufacturing a solid state lighting (SSL) device, comprising:
attaching a formation structure to a composite structure, the composite structure having a composite coefficient of thermal expansion (CTE) dependency over a temperature range, the composite structure containing a base material and a CTE control material contained within the base material, the base material including a single crystalline material or a polycrystalline material;
reducing a thickness of the formation structure attached to the composite structure; and
forming an SSL structure on the formation structure with the reduced thickness, the SSL structure having an SSL CTE temperature dependency over the temperature range,
wherein a difference between the composite and SSL CTE temperature dependencies is below a target threshold over at least a portion of the temperature range, and wherein
the base material of the composite structure contains polycrystalline aluminum nitride (AlN) and the CTE control material contains yttrium oxide (Y 2 O 3 ) and hafnium carbide (HfC) as follows:
AlN x :Y 2 O 3 ( y ):HfC( 1-x-y ), where x is about 0.4 to about 0.7, and y is about 0.01 to about 0.1.
10. A method for manufacturing a solid state lighting (SSL) device, comprising:
attaching a formation structure to a composite structure having a base material and a coefficient of thermal expansion (CTE) control material, the composite structure having a composite CTE temperature dependency over a temperature range, the composite structure containing a base material and a CTE control material contained within the base material, the base material including a single crystalline material or a polycrystalline material;
forming an SSL structure on the formation structure, the SSL structure having an SSL CTE temperature dependency over the temperature range; and
selecting at least one of a composition of the base material, a composition of the CTE control material, and a volume ratio of the base material to the CTE control material based on a target CTE difference between the composite CTE temperature dependency and the SSL CTE temperature dependency over at least a portion of the temperature range,
wherein
the base material contains polycrystalline aluminum nitride (AlN),
the CTE control material contains yttrium oxide (Y 2 O 3 ), and
selecting includes selecting the volume ratio of the base material to the CTE control material such that a difference between the composite CTE temperature dependency and the SSL CTE temperature dependency is lower than 3 ppm/° C. over the temperature range.
11. The method of claim 10 wherein:
the CTE control material further contains at least one of silicon nitride (Si 3 N 4 ), titanium nitride (TiN), zirconium nitride (ZrN), hafnium nitride (HfN), silicon oxide (SiO 2 ), aluminum oxide (Al 2 O 3 ), aluminum oxynitride (AlON), titanium carbide (TiC), zirconium carbide (ZrC), hafnium carbide (HfC), silicon carbide (SiC); and
selecting further includes selecting the composition of the CTE control material and the volume ratio of the base material to the CTE control material such that a difference between the composite CTE temperature dependency and the SSL CTE temperature dependency is lower than 3 ppm/° C. over the temperature range.
12. The method of claim 10 wherein selecting further includes at least one of the composition of the base material and the composition of the CTE control material such that a difference between the composite CTE temperature dependency and the SSL CTE temperature dependency is lower than 3 ppm/° C. over the temperature range.
13. The method of claim 10 wherein:
the CTE control material includes a first CTE control material and a second CTE control material; and
selecting further includes:
selecting at least one of the composition of the base material and the composition of the first CTE control material such that a first difference between the composite CTE temperature dependency and the SSL CTE temperature dependency is lower than 3 ppm/° C. over a first temperature range; and
selecting at least one of the composition of the base material and a composition of the second CTE control material such that a second difference between the composite CTE temperature dependency and the SSL CTE temperature dependency is lower than 3 ppm/° C. over a second temperature range.
14. The method of claim 10 wherein:
the CTE control material includes a first CTE control material and a second CTE control material; and
selecting further includes:
selecting a composition of the first CTE control material based on a temperature dependency of the first CTE control material in a first temperature range; and
selecting a composition of the second CTE control material based on a temperature dependency of the second CTE control material in a second temperature range.
15. The method of claim 10 wherein:
the CTE control material includes a first CTE control material and a second CTE control material; and
selecting further includes:
selecting a composition of the first CTE control material based on a temperature dependency of the first CTE control material relative to the SSL CTE temperature dependency in a first temperature range; and
selecting a composition of the second CTE control material based on a temperature dependency of the second CTE control material relative to the SSL CTE temperature dependency in a second temperature range.
16. The method of claim 10 wherein selecting further includes selecting the composition of the CTE control material based on a temperature dependency of the CTE control material relative to the SSL CTE temperature dependency in the temperature range.
17. The method of claim 10 wherein selecting further includes:
selecting the composition of the base material based on a temperature dependency of the base material relative to the SSL CTE temperature dependency in the temperature range; and
selecting the composition of the CTE control material based on temperature dependencies of the CTE control material and the base material relative to the SSL CTE temperature dependency in the temperature range.
18. The method of claim 9 wherein the difference between the composite and SSL CTE temperature dependencies is below the target threshold over the entire temperature range.
19. The method of claim 9 wherein the difference between the composite and SSL CTE temperature dependencies is between about 1 ppm/° C. and 3 ppm/° C. over the entire temperature range.
20. The method of claim 9 wherein an integrated difference between the composite and SSL CTE temperature dependencies over the temperature range is below the target threshold.