Epitaxial formation support structures and associated methods
View Patent ↗Epitaxial formation support structures and associated methods of manufacturing epitaxial formation support structures and solid state lighting devices are disclosed herein. In several embodiments, a method of manufacturing an epitaxial formation support substrate can include forming an uncured support substrate that has a first side, a second side opposite the first side, and coefficient of thermal expansion substantially similar to N-type gallium nitride. The method can further include positioning the first side of the uncured support substrate on a first surface of a first reference plate and positioning a second surface of a second reference plate on the second side to form a stack. The first and second surfaces can include uniformly flat portions. The method can also include firing the stack to sinter the uncured support substrate. At least side of the support substrate can form a planar surface that is substantially uniformly flat.
1. A solid state lighting (SSL) device, comprising:
a cured support substrate having a sintered planar surface, wherein the support substrate has a coefficient of thermal expansion (CTE) substantially similar to that of N-type gallium nitride (GaN);
a formation structure directly bonded to the sintered planar surface of the support substrate; and
an SSL structure directly on the formation structure, wherein the SSL structure includes at least a first semiconductor material epitaxially grown on the formation structure,
wherein the sintered planar surface of the support substrate is uniformly flat such that any warp from the support substrate to the SSL structure is substantially eliminated.
2. The SSL device of claim 1 wherein:
the support substrate comprises aluminum nitride; and
the formation structure comprises silicon;
the first semiconductor material comprises N-type GaN; and
the SSL structure further comprises a second semiconductor material made of P-type GaN and an active region between the first and second semiconductor materials.
3. The SSL device of claim 1 wherein the support substrate includes a polycrystalline ceramic.
4. The SSL device of claim 3 wherein the polycrystalline ceramic comprises at least one of Si 3 N 4 , TiN, HfN, AlN, SiO 2 , Al 2 O 3 , AlON, TiC, ZrC, HfC, SiC, and Y 2 O 3 .
5. The SSL device of claim 1 wherein the warp from the support substrate to the SSL structure is less than 25 micrometers.
6. The SSL device of claim 1 , further comprising a bonding region bonded to the planar surface of the support substrate, wherein the bonding region is doped with at least one of Boron and Helium.
7. The SSL device of claim 1 wherein the support substrate and the formation structure are directly bonded to each other via a metal-metal bond.
8. A solid state lighting (SSL) device, comprising:
a cured support substrate having a sintered planar surface, wherein the support substrate has a coefficient of thermal expansion (CTE) substantially similar to that of III-nitrides, wherein the planar surface of the support substrate is formed by curing the support substrate between two reference plates;
a formation structure directly bonded to the sintered planar surface of the support substrate; and
an SSL structure directly on the formation structure, wherein the SSL structure includes at least a first semiconductor material epitaxially grown on the formation structure, an active region on the first semiconductor material, and a second semiconductor material on the active region,
wherein the sintered planar surface of the support substrate is uniformly flat such that any warp from the support substrate to the SSL structure is substantially eliminated.
9. The SSL device of claim 8 wherein the support substrate is a polycrystalline ceramic material.
10. The SSL device of claim 8 wherein the support substrate comprises at least one of Si 3 N 4 , TiN, HfN, SiO 2 , Al 2 O 3 , AlON, TiC, ZrC, HfC, SiC, and Y 2 O 3 .