Patents by Inventor Jennifer Mary Barnes
Jennifer Mary Barnes has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).
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Patent number: 8073031Abstract: A laser diode structure that includes two different insulator layers, one to maintain good optical confinement, typically located at the sides of the laser ridge, and another to improve the heat dissipation properties, typically located on the etched surfaces away from the ridge.Type: GrantFiled: March 3, 2008Date of Patent: December 6, 2011Assignee: Sharp Kabushiki KaishaInventors: Wei-Sin Tan, Jennifer Mary Barnes
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Patent number: 7629237Abstract: A method of MBE growth of a semiconductor layer structure comprises growing a first (Al,Ga)N layer (step 13) over a substrate at the first substrate temperature (T1) using ammonia as the nitrogen precursor. The substrate is then cooled (step 14) to a second-substrate temperature (T2) which is lower than the first substrate temperature. An (In,Ga)N quantum well structure is then grown (step 15) over the first (Al,Ga)N layer by MBE using ammonia as the nitrogen precursor. The supply of ammonia to the substrate is maintained continuously during the first growth step, the cooling step, and the second growth step. After completion of the growth of the (In,Ga)N quantum well structure, the substrate may be heated to a third temperature (T3) which is greater than the second substrate temperature (T2). A second (Al,Ga)N layer is then grown over the (In,Ga)N quantum well structure (step 17).Type: GrantFiled: August 18, 2003Date of Patent: December 8, 2009Assignee: Sharp Kabushiki KaishaInventors: Valerie Bousquet, Stewart Edward Hooper, Jennifer Mary Barnes, Jonathan Heffernan
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Publication number: 20090219966Abstract: A laser diode structure that includes two different insulator layers, one to maintain good optical confinement, typically located at the sides of the laser ridge, and another to improve the heat dissipation properties, typically located on the etched surfaces away from the ridge.Type: ApplicationFiled: March 3, 2008Publication date: September 3, 2009Inventors: Wei-Sin TAN, Jennifer Mary Barnes
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Patent number: 7504321Abstract: A method of growing an AlGaN semiconductor layer structure by Molecular Beam Epitaxy comprises supplying ammonia, gallium and aluminum to a growth chamber thereby to grow a first (Al,Ga)N layer by MBE over a substrate disposed in the growth chamber. The first (Al,Ga)N layer has a non-zero aluminum mole fraction. Ammonia is supplied at a beam equivalent pressure of at least 1 10?4 mbar, gallium is supplied at a beam equivalent pressure of at least 1 10?8 mbar and aluminum is supplied at a beam equivalent pressure of at least 1 10?8 mbar during the growth step. Once the first (Al,Ga)N layer has been grown, varying the supply rate of gallium and/or aluminum enables a second (Al,Ga)N layer, having a different aluminum mole fraction from the first (Al,Ga)N layer to be grown by MBE over the first (Al,Ga)N layer. This process may be repeated to grown an (Al,Ga)N multilayer structure.Type: GrantFiled: August 18, 2003Date of Patent: March 17, 2009Assignee: Sharp Kabushiki KaishaInventors: Valerie Bousquet, Stewart Edward Hooper, Jennifer Mary Barnes, Katherine L. Johnson, Jonathan Heffernan
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Patent number: 7358112Abstract: A method of growing a p-type nitride semiconductor material having magnesium as a p-type dopant by molecular beam epitaxy (MBE), comprises supplying ammonia gas, gallium and magnesium to an MBE growth chamber containing a substrate so as to grow a p-type nitride semiconductor material over the substrate. Magnesium is supplied to the growth chamber at a beam equivalent pressure of at least 1 10-9 mbar, and preferably in the range from 1 10-9 mbar to 1 10-7 mbar during the growth process. This provides p-type GaN that has a high concentration of free charge carriers and eliminates the need to activate the magnesium dopant atoms by annealing or irradiating the material.Type: GrantFiled: June 13, 2002Date of Patent: April 15, 2008Assignee: Sharp Kabushiki KaishaInventors: Jennifer Mary Barnes, Valerie Bousquet, Stewart Edward Hooper, Jonathan Heffernan
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Patent number: 7115167Abstract: The invention provides a method of growing an (In, Ga)N multiplayer structure by molecular beam epitaxy. Each GaN or InGaN layer in the multilayer structure is grown at a substrate temperature of at least 650° C., and this provides improved material quality. Ammonia gas is used as the source of nitrogen for the growth process. Ammonia and gallium are supplied to the growth chamber at substantially constant rates, and the supply rate of indium to the growth chamber is varied to select the desired composition for the layer being grown. This allows the structure to be grown at a substantially constant growth rate. The substrate temperature is preferably kept constant during the growth process, to avoid the need to interrupt the growth process to vary the substrate temperature between the growth of one layer and the growth of another layer.Type: GrantFiled: February 19, 2002Date of Patent: October 3, 2006Assignee: Sharp Kabushiki KaishaInventors: Stewart Edward Hooper, Jennifer Mary Barnes, Valerie Bousquet, Jonathan Heffernan
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Publication number: 20040214412Abstract: A method of growing a p-type nitride semiconductor material having magnesium as a p-type dopant by molecular beam epitaxy (MBE), comprises supplying ammonia gas, gallium and magnesium to an MBE growth chamber containing a substrate so as to grow a p-type nitride semiconductor material over the substrate. Magnesium is supplied to the growth chamber at a beam equivalent pressure of at least 1 10-9 mbar, and preferably in the range from 1 10-9 mbar to 1 10-7 mbar during the growth process. This provides p-type GaN that has a high concentration of free charge carriers and eliminates the need to activate the magnesium dopant atoms by annealing or irradiating the material.Type: ApplicationFiled: May 24, 2004Publication date: October 28, 2004Inventors: Jennifer Mary Barnes, Valerie Bousquet, Stewart Edward Hooper, Jonathan Heffernan
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Patent number: 6500258Abstract: This invention relates to a method of growing a nitride semiconductor layer by molecular beam epitaxy comprising the steps of: a) heating a GaN substrate (S) disposed in a growth chamber (10) to a substrate temperature of at least 850° C.; and b) growing a nitride semiconductor layer on the GaN substrate by molecular beam epitaxy at a substrate temperature of at least 850° C., ammonia gas being supplied to the growth chamber (10) during the growth of the nitride semiconductor layer; wherein the method comprises the further step of commencing the supply ammonia gas to the growth chamber during step (a), before the substrate temperature has reached 800° C.Type: GrantFiled: June 18, 2001Date of Patent: December 31, 2002Assignee: Sharp Kabushiki KaishaInventors: Stewart Edward Hooper, Jonathan Heffernan, Jennifer Mary Barnes, Alistair Henderson Kean
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Publication number: 20020117103Abstract: The invention provides a method of growing an (In,Ga)N multilayer structure by molecular beam epitaxy. Each GaN or InGaN layer in the multilayer structure is grown at a substrate temperature of at least 650° C., and this provides improved material quality. Ammonia gas is used as the source of nitrogen for the growth process.Type: ApplicationFiled: February 19, 2002Publication date: August 29, 2002Inventors: Stewart Edward Hooper, Jennifer Mary Barnes, Valerie Bousquet, Jonathan Heffernan
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Patent number: 6440214Abstract: A method of growing a nitride semiconductor layer, such as a GaN layer, by molecular beam epitaxy comprises the step of growing a GaAlN nucleation layer on a substrate by molecular beam epitaxy. The nucleation layer is annealed, and a nitride semiconductor layer is then grown over the nucleation layer by molecular beam epitaxy. The nitride semiconductor layer is grown at a V/III molar ratio of 100 or greater, and this enables a high substrate temperature to be used so that a good quality semiconductor layer is obtained. Ammonia gas is supplied during the growth process, to provide the nitrogen required for the MBE growth process.Type: GrantFiled: June 9, 2000Date of Patent: August 27, 2002Assignee: Sharp Kabushiki KaishaInventors: Stewart Edward Hooper, Jennifer Mary Barnes, Jonathan Heffernan, Alistair Henderson Kean
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Publication number: 20020015866Abstract: This invention relates to a method of growing a nitride semiconductor layer by molecular beam epitaxy comprising the steps of: a) heating a GaN substrate (S) disposed in a growth chamber (10) to a substrate temperature of at least 850° C.; and b) growing a nitride semiconductor layer on the GaN substrate by molecular beam epitaxy at a substrate temperature of at least 850° C., ammonia gas being supplied to the growth chamber (10) during the growth of the nitride semiconductor layer; wherein the method comprises the further step of commencing the supply ammonia gas to the growth chamber during step (a), before the substrate temperature has reached 800° C.Type: ApplicationFiled: June 18, 2001Publication date: February 7, 2002Inventors: Stewart Edward Hooper, Jonathan Heffernan, Jennifer Mary Barnes, Alistair Henderson Kean