US 12,264,410 B2
Aluminum nitride crystals having low urbach energy and high transparency to deep-ultraviolet wavelengths
Robert T. Bondokov, Watervliet, NY (US); James R. Grandusky, Waterford, NY (US); Jianfeng Chen, Ballston Lake, NY (US); Shichao Wang, Troy, NY (US); Toru Kimura, Tokyo (JP); Thomas Miebach, Malta, NY (US); Keisuke Yamaoka, Tokyo (JP); and Leo J. Schowalter, Latham, NY (US)
Assigned to CRYSTAL IS, INC., Green Island, NY (US)
Filed by Robert T. Bondokov, Watervliet, NY (US); James R. Grandusky, Waterford, NY (US); Jianfeng Chen, Ballston Lake, NY (US); Shichao Wang, Troy, NY (US); Toru Kimura, Tokyo (JP); Thomas Miebach, Malta, NY (US); Keisuke Yamaoka, Tokyo (JP); and Leo J. Schowalter, Latham, NY (US)
Filed on Dec. 13, 2022, as Appl. No. 18/080,008.
Application 18/080,008 is a continuation of application No. 16/444,147, filed on Jun. 18, 2019, granted, now 11,555,256.
Claims priority of provisional application 62/686,883, filed on Jun. 19, 2018.
Prior Publication US 2023/0183883 A1, Jun. 15, 2023
Int. Cl. C30B 29/40 (2006.01); C01B 21/072 (2006.01); C30B 23/06 (2006.01); C30B 33/02 (2006.01); H01L 33/32 (2010.01)
CPC C30B 29/403 (2013.01) [C30B 23/066 (2013.01); C30B 33/02 (2013.01); H01L 33/32 (2013.01); C01B 21/072 (2013.01); C01P 2006/60 (2013.01)] 25 Claims
OG exemplary drawing
 
1. An annealed single-crystal AlN substrate having (i) a thermal conductivity of at least 250 W/mK and (ii) an ultraviolet (UV) absorption coefficient that is:
a) less than 10 cm−1 and no less than 5 cm−1 for an entire wavelength range of 220 nm to 450 nm,
b) less than 9 cm−1 and no less than 5 cm−1 for an entire wavelength range of 350 nm to 450 nm, and
c) within ±2 cm−1 for an entire wavelength range of 220 nm to 280 nm,
wherein the single-crystal AlN substrate is cut from a single-crystal AlN boule having a diameter of the boule that is at least 25 mm and no more than 150 mm, wherein the diameter increases over a portion of a length of the boule, the length of the boule being at least 0.5 cm.