Masanori Ikari

US Patent:

8236267, Aug 7, 2012

Filed:

Jun 4, 2009

Appl. No.:

12/455683

Inventors:

Tadao Hashimoto - Santa Barbara CA, US
Edward Letts - Buellton CA, US
Masanori Ikari - Santa Barbara CA, US

Assignee:

Sixpoint Materials, Inc. - Buellton CA

International Classification:

C01B 21/06
C30B 23/00
C23C 16/00

US Classification:

423409, 117 88, 117 95, 117 97, 118715, 118725

Abstract:

The present invention discloses a high-pressure vessel of large size formed with a limited size of e. g. Ni—Cr based precipitation hardenable superalloy. The vessel may have multiple zones. For instance, the high-pressure vessel may be divided into at least three regions with flow-restricting devices and the crystallization region is set higher temperature than other regions. This structure helps to reliably seal both ends of the high-pressure vessel, and at the same time, may help to greatly reduce unfavorable precipitation of group III nitride at the bottom of the vessel. This invention also discloses novel procedures to grow crystals with improved purity, transparency and structural quality. Alkali metal-containing mineralizers are charged with minimum exposure to oxygen and moisture until the high-pressure vessel is filled with ammonia. Several methods to reduce oxygen contamination during the process steps are presented.

US Patent:

8357243, Jan 22, 2013

Filed:

Jun 12, 2009

Appl. No.:

12/456181

Inventors:

Tadao Hashimoto - Santa Barbara CA, US
Masanori Ikari - Santa Barbara CA, US
Edward Letts - Buellton CA, US

Assignee:

Sixpoint Materials, Inc. - Buellton CA

International Classification:

C30B 23/00
C30B 25/00
C30B 28/12
C30B 28/14

US Classification:

117101, 117 84, 117 85, 117 88, 117 97

Abstract:

The present invention discloses a new testing method of group III-nitride wafers. By utilizing the ammonothermal method, GaN or other Group III-nitride wafers can be obtained by slicing the bulk GaN ingots. Since these wafers originate from the same ingot, these wafers have similar properties/qualities. Therefore, properties of wafers sliced from an ingot can be estimated from measurement data obtained from selected number of wafers sliced from the same ingot or an ingot before slicing. These estimated properties can be used for product certificate of untested wafers. This scheme can reduce a significant amount of time, labor and cost related to quality control.

US Patent:

8420041, Apr 16, 2013

Filed:

Jun 7, 2012

Appl. No.:

13/491392

Inventors:

Tadao Hashimoto - Santa Barbara CA, US
Edward Letts - Buellton CA, US
Masanori Ikari - Santa Barbara CA, US

Assignee:

Sixpoint Materials, Inc. - Buellton CA

International Classification:

C01B 21/06
C30B 23/00
C23C 16/00

US Classification:

423409, 117 88, 117 95, 117 97, 118715, 118725

Abstract:

The present invention discloses a high-pressure vessel of large size formed with a limited size of e. g. Ni—Cr based precipitation hardenable superalloy. Vessel may have multiple zones. For instance, the high-pressure vessel may be divided into at least three regions with flow-restricting devices and the crystallization region is set higher temperature than other regions. This structure helps to reliably seal both ends of the high-pressure vessel, at the same time, may help to greatly reduce unfavorable precipitation of group III nitride at the bottom of the vessel. Invention also discloses novel procedures to grow crystals with improved purity, transparency and structural quality. Alkali metal-containing mineralizers are charged with minimum exposure to oxygen and moisture until the high-pressure vessel is filled with ammonia. Several methods to reduce oxygen contamination during the process steps are presented. Back etching of seed crystals and a new temperature ramping scheme to improve structural quality are disclosed.

US Patent:

8557043, Oct 15, 2013

Filed:

Dec 27, 2012

Appl. No.:

13/728799

Inventors:

Masanori Ikari - Santa Barbara CA, US
Edward Letts - Buellton CA, US

Assignee:

SixPoint Materials, Inc. - Buellton CA

International Classification:

C30B 23/00
C30B 25/00
C30B 28/12
C30B 28/14

US Classification:

117101, 117 84, 117 85, 117 88

Abstract:

The present invention discloses a new testing method of group III-nitride wafers. By utilizing the ammonothermal method, GaN or other Group III-nitride wafers can be obtained by slicing the bulk GaN ingots. Since these wafers originate from the same ingot, these wafers have similar properties/qualities. Therefore, properties of wafers sliced from an ingot can be estimated from measurement data obtained from selected number of wafers sliced from the same ingot or an ingot before slicing. These estimated properties can be used for product certificate of untested wafers. This scheme can reduce a significant amount of time, labor and cost related to quality control.

US Patent:

8585822, Nov 19, 2013

Filed:

Dec 27, 2012

Appl. No.:

13/728769

Inventors:

Masanori Ikari - Santa Barbara CA, US
Edward Letts - Buellton CA, US

Assignee:

Sixpoint Materials, Inc. - Buellton CA

International Classification:

C30B 23/00
C30B 25/00
C30B 28/12
C30B 28/14

US Classification:

117101, 117 84, 117 85, 117 88, 117 91

Abstract:

The present invention discloses a new testing method of group III-nitride wafers. By utilizing the ammonothermal method, GaN or other Group III-nitride wafers can be obtained by slicing the bulk GaN ingots. Since these wafers originate from the same ingot, these wafers have similar properties/qualities. Therefore, properties of wafers sliced from an ingot can be estimated from measurement data obtained from selected number of wafers sliced from the same ingot or an ingot before slicing. These estimated properties can be used for product certificate of untested wafers. This scheme can reduce a significant amount of time, labor and cost related to quality control.

US Patent:

20090256240, Oct 15, 2009

Filed:

Feb 25, 2009

Appl. No.:

12/392960

Inventors:

Tadao HASHIMOTO - Santa Barbara CA, US
Edward Letts - Buellton CA, US
Masanori Ikari - Santa Barbara CA, US

International Classification:

H01L 29/20
H01L 21/322

US Classification:

257615, 438471, 257E21322, 257E29089

Abstract:

The present invention discloses a production method for group III nitride ingots or pieces such as wafers. To solve the coloration problem in the wafers grown by the ammonothermal method, the present invention composed of the following steps; growth of group III nitride ingots by the ammonothermal method, slicing of the ingots into wafers, annealing of the wafers in a manner that avoids dissociation or decomposition of the wafers. This annealing process is effective to improve transparency of the wafers and/or otherwise remove contaminants from wafers.

US Patent:

20090309105, Dec 17, 2009

Filed:

Jun 4, 2009

Appl. No.:

12/455760

Inventors:

Edward Letts - Buellton CA, US
Tadao Hashimoto - Santa Barbara CA, US
Masanori Ikari - Santa Barbara CA, US

International Classification:

H01L 29/20
H01L 21/20

US Classification:

257 76, 438478, 257E2109, 257E29089

Abstract:

The present invention discloses methods to create higher quality group III-nitride wafers that then generate improvements in the crystalline properties of ingots produced by ammonothermal growth from an initial defective seed. By obtaining future seeds from carefully chosen regions of an ingot produced on a bowed seed crystal, future ingot crystalline properties can be improved. Specifically, the future seeds are optimized if chosen from an area of relieved stress on a cracked ingot or from a carefully chosen N-polar compressed area. When the seeds are sliced out, miscut of 3-10 helps to improve structural quality of successive growth. Additionally a method is proposed to improve crystal quality by using the ammonothermal method to produce a series of ingots, each using a specifically oriented seed from the previous ingot. When employed, these methods enhance the quality of Group III nitride wafers and thus improve the efficiency of any subsequent device.

US Patent:

20100095882, Apr 22, 2010

Filed:

Oct 16, 2009

Appl. No.:

12/580849

Inventors:

Tadao Hashimoto - Santa Barbara CA, US
Masanori Ikari - Santa Barbara CA, US
Edward Letts - Buellton CA, US

International Classification:

C30B 7/10
B01J 3/04

US Classification:

117 71, 117224

Abstract:

The present disclosure proves for new design of reactors used for ammonothermal growth of III nitride crystals. The reactors include a region intermediate a source dissolution region and a crystal growth region configured to provide growth of high quality crystals at rates greater than 100 μm/day. In one embodiment, multiple baffle plates having openings whose location is designed so that there is no direct path through the intermediate region, or with multiple baffle plates having differently sized openings on each plate so that the flow is slowed down and/or exhibit greater mixing are described. The disclosed designs enables obtaining high temperature difference between the dissolution region and the crystallization region without decreasing conductance through the device.