Ishwara Bhat - Academia.edu (original) (raw)

Papers by Ishwara Bhat

Research paper thumbnail of <title>Vapor phase epitaxy of ZnTe on silicon substrates</title>

Growth and Characterization of Materials for Infrared Detectors, 1993

ABSTRACT

Research paper thumbnail of Growth and properties of Hg(1-x)Cd(x)Te on GaAs substrates by organometallic vapor-phase epitaxy

J Appl Phys, 1986

Growth of epitaxial mercury cadmium telluride (Hg/1-x/Cd/x/Te) on (100) GaAs substrates by organo... more Growth of epitaxial mercury cadmium telluride (Hg/1-x/Cd/x/Te) on (100) GaAs substrates by organometallic vapor-phase epitaxy is described. Transport measurements made on these layers at 80 K indicate an electron mobility greater than 200,000 sq cm/V s for layers of composition x = to about 0.2. An intervening CdTe buffer layer was used to accommodate the large (14 percent) lattice mismatch between these systems, and HgCdTe layers have been grown with CdTe buffer layer thicknesses from 1000 A to 3 microns. It is shown that a CdTe buffer layer of 2-3 microns is necessary to accommodate the misfit dislocations at the CdTe-GaAs interface.

Research paper thumbnail of Improving Switching Characteristics of 4H-SiC Junction Rectifiers Using Epitaxial and Implanted Anodes with Epitaxial Refill

Materials Science Forum, 2006

Abstract The on-state and switching performance of high voltage 4H-SiC junction rectifiers are co... more Abstract The on-state and switching performance of high voltage 4H-SiC junction rectifiers are compared using numerical simulations and experimental characterization. Epitaxial and implanted anode PiN diodes as well as novel, advanced rectifiers have been fabricated in ...

Research paper thumbnail of 1.5kV Novel 4H-SiC Lateral Channel (LC) JBS Rectifiers with Low Leakage Current and Capacitance

Proceedings. ISPSD '05. The 17th International Symposium on Power Semiconductor Devices and ICs, 2005., 2000

Page 1. 1.5kV Novel 4H-SiC Lateral Channel (LC) JBS Rectifiers with Low Leakage Current and Capac... more Page 1. 1.5kV Novel 4H-SiC Lateral Channel (LC) JBS Rectifiers with Low Leakage Current and Capacitance Lin Zhu1, Canhua Li1, T. Paul Chow1, Ishwara B Bhat1, Kenneth A. Jones2, C. Scozzie2 and Anant Agarwal3 1Center ...

Research paper thumbnail of Selective Growth of 4H-SiC on 4H-SiC Substrates using a High Temperature Mask

Materials Science Forum, 2004

Abstract. Selective growth of SiC on SiC substrate was demonstrated in a chemical vapor depositio... more Abstract. Selective growth of SiC on SiC substrate was demonstrated in a chemical vapor deposition (CVD) reactor using a new high temperature mask. Bulk 4H-SiC with 8o miscut (0001) Si-face wafers were coated with the high temperature mask and patterned using ...

Research paper thumbnail of High-voltage 4H-SiC PiN rectifiers with single-implant, multi-zone JTE termination

Proceedings of the 16th International Symposium on Power Semiconductor Devices & IC's, 2004

Abstract A novel multi-zone junction termination extension (MZJTE) is presented for high-voltage ... more Abstract A novel multi-zone junction termination extension (MZJTE) is presented for high-voltage 4H-SiC pin junction rectifiers. Unlike the conventional multi-implantation or SiC etching approaches, our new termination technique utilizes multiple masking oxide ...

Research paper thumbnail of Growth and properties of Hg 1-x Cd x Te on GaAs, with x - 0.27

J Electron Mater, 1988

The organometallic vapor phase epitaxy of HgCdTe onto (100)2-(110) GaAs substrates is described i... more The organometallic vapor phase epitaxy of HgCdTe onto (100)2-(110) GaAs substrates is described in this paper. A buffer layer of CdTe has been grown prior to the growth of HgCdTe, to take up the large lattice mismatch with the GaAs. Considerations for the thickness of this buffer layer are outlined, and it is shown by quantitative Secondary Ion Mass Spectroscopy

Research paper thumbnail of Steady-state and dynamic analyses of high-order parallel resonant convertors

Electric Power Applications Iee Proceedings B See Also Iee Proceedings Electric Power Applications, May 1, 1993

Research paper thumbnail of Electrical Characteristics and Carrier Lifetime Measurements in High Voltage 4H-SIC Pin Diodes

The key material and device parameters governing the electrical performance of high voltage 4H-Si... more The key material and device parameters governing the electrical performance of high voltage 4H-SiC PiN diodes have been investigated using experimental results and numerical simulations. Reverse recovery characteristics show an increase in both carrier lifetime and anode injection efficiency at elevated temperature. Open circuit voltage decay measurements are used to estimate carrier lifetimes (τ ≈ 0.6μs at T=25°C increasing to τ≈2μs at T=225°C) that are comparable to values measured on starting material prior to fabrication using micro-wave photoconductivity decay techniques.

Research paper thumbnail of Characteristics of Trench-Refilled 4H-SiC P-N Junction Diodes Fabricated by Selective Epitaxial Growth

Materials Science Forum, Feb 15, 2005

Abstract Selective nitrogen doping of 4H-SiC by epitaxial growth using TaC as the high temperatur... more Abstract Selective nitrogen doping of 4H-SiC by epitaxial growth using TaC as the high temperature mask has been demonstrated. Nomarski optical microscope and scanning electron microscope (SEM) were used to characterize selective growth of SiC. In addition, ...

Research paper thumbnail of A Study of Electrical Properties of Mg-Doped GaN Grown by Metalorganic Vapor Phase Epitaxy

Research paper thumbnail of Photovoltaic properties of CdTe layers grown by OMVPE

Photovoltaic characteristics of single-crystal cadmium telluride epitaxial layers grown by organo... more Photovoltaic characteristics of single-crystal cadmium telluride epitaxial layers grown by organometallic vapor phase epitaxy (OMVPE) on InSb substrates are reported. Electrical characterization of Schottky solar cells fabricated by depositing thin transparent gold shows that a hole diffusion length of 2 microns can be obtained in n-CdTe. The current flow in the p-n junction in the forward bias is determined by

Research paper thumbnail of CdTe Films Grown on InSb Substrates by Organometallic Epitaxy

MRS Proceedings, 1986

Title: CdTe films grown on InSb substrates by organometallic epitaxy. Authors: Bhat, IB; Taskar, ... more Title: CdTe films grown on InSb substrates by organometallic epitaxy. Authors: Bhat, IB; Taskar, NR; Ayers, J.; Patel, K.; Ghandhi, SK. ... Growth at 350 C resulted in the smallest x-ray rocking curve (DGRC) full width at half maximum (FWHM) of about 20 arc seconds.

Research paper thumbnail of High Voltage 4H-SiC Epitaxial Emitter BJTs using a Self-aligned Selectively Re-grown Base Contact

Hitherto, all 4H-SiC based epitaxial emitter BJTs demonstrated [1, 2], exhibit a specific on-resi... more Hitherto, all 4H-SiC based epitaxial emitter BJTs demonstrated [1, 2], exhibit a specific on-resistance (Ron,, p) value higher than the unipolar value for their drift regions. One way to reduce Ron, sp is to minimize the extrinsic base resistance by bringing the base contact ...

Research paper thumbnail of Degraded blocking performance of 4H-SiC rectifiers under high dV/dt conditions

Research paper thumbnail of Boron Filling of Deep Holes for Solid-State Neutron Detector Applications

Research paper thumbnail of Electrostatic Force Microscopy and Secondary Electron Imaging of Double Stacking Faults in Heavily n-type 4H-SiC after Oxidation

MRS Proceedings, 2003

... 742, K3.4.1 (2003). 7. BJ Skromme, MK Mikhov, L. Chen, G. Samson, R. Wang, C. Li, and I. Bhat... more ... 742, K3.4.1 (2003). 7. BJ Skromme, MK Mikhov, L. Chen, G. Samson, R. Wang, C. Li, and I. Bhat, to be published in Mater. Sci. Forum. 8. A. Henry, A. Ellison, U. Forsberg, B. Magnusson, G. Pozina and E. Janzén: Mater. Sci. Forum 389-393, 593 (2002). ...

Research paper thumbnail of Electrical Characterization of Magnesium-Doped Gallium Nitride Grown by Metalorganic Vapor Phase Epitaxy

MRS Online Proceeding Library

Research paper thumbnail of Characteristics of Trench-Refilled 4H-SiC P-N Junction Diodes Fabricated by Selective Epitaxial Growth

Materials Science Forum, 2005

Abstract Selective nitrogen doping of 4H-SiC by epitaxial growth using TaC as the high temperatur... more Abstract Selective nitrogen doping of 4H-SiC by epitaxial growth using TaC as the high temperature mask has been demonstrated. Nomarski optical microscope and scanning electron microscope (SEM) were used to characterize selective growth of SiC. In addition, ...

Research paper thumbnail of Surface studies of SiC epitaxial layers grown by chemical vapor deposition

Materials Science and Engineering: B, 2006

We have systematically carried out investigations on the growth of SiC epitaxial layers by varyin... more We have systematically carried out investigations on the growth of SiC epitaxial layers by varying C/Si ratio over the range of 0.5, 1.0, 3.0, 6.0, and 9.0 in the gas phase. The studies by an optical Nomarski microscope and an atomic force microscope revealed the growth of hillocks and nano-tube like structures for particular deposition conditions on the C-face (0 0 01) and Si-face (0 0 0 1) 4H-SiC substrates. Indeed, at extreme conditions, the triangular shape hillocks formation was found on the C-face 4H-SiC substrates whereas on the Si-face 4H-SiC substrates, the cone or dome shape structures exhibited were black in color. Several carrot-like type structures, pits, etc., were also observed on the surface of the epilayers, which affect the quality of the layers and reduce the device efficiency. At optimized conditions, the surface looked like featureless with low roughness. In addition to C/Si ratios, N 2 dopant into SiC epitaxial layers have also been studied.

Research paper thumbnail of <title>Vapor phase epitaxy of ZnTe on silicon substrates</title>

Growth and Characterization of Materials for Infrared Detectors, 1993

ABSTRACT

Research paper thumbnail of Growth and properties of Hg(1-x)Cd(x)Te on GaAs substrates by organometallic vapor-phase epitaxy

J Appl Phys, 1986

Growth of epitaxial mercury cadmium telluride (Hg/1-x/Cd/x/Te) on (100) GaAs substrates by organo... more Growth of epitaxial mercury cadmium telluride (Hg/1-x/Cd/x/Te) on (100) GaAs substrates by organometallic vapor-phase epitaxy is described. Transport measurements made on these layers at 80 K indicate an electron mobility greater than 200,000 sq cm/V s for layers of composition x = to about 0.2. An intervening CdTe buffer layer was used to accommodate the large (14 percent) lattice mismatch between these systems, and HgCdTe layers have been grown with CdTe buffer layer thicknesses from 1000 A to 3 microns. It is shown that a CdTe buffer layer of 2-3 microns is necessary to accommodate the misfit dislocations at the CdTe-GaAs interface.

Research paper thumbnail of Improving Switching Characteristics of 4H-SiC Junction Rectifiers Using Epitaxial and Implanted Anodes with Epitaxial Refill

Materials Science Forum, 2006

Abstract The on-state and switching performance of high voltage 4H-SiC junction rectifiers are co... more Abstract The on-state and switching performance of high voltage 4H-SiC junction rectifiers are compared using numerical simulations and experimental characterization. Epitaxial and implanted anode PiN diodes as well as novel, advanced rectifiers have been fabricated in ...

Research paper thumbnail of 1.5kV Novel 4H-SiC Lateral Channel (LC) JBS Rectifiers with Low Leakage Current and Capacitance

Proceedings. ISPSD '05. The 17th International Symposium on Power Semiconductor Devices and ICs, 2005., 2000

Page 1. 1.5kV Novel 4H-SiC Lateral Channel (LC) JBS Rectifiers with Low Leakage Current and Capac... more Page 1. 1.5kV Novel 4H-SiC Lateral Channel (LC) JBS Rectifiers with Low Leakage Current and Capacitance Lin Zhu1, Canhua Li1, T. Paul Chow1, Ishwara B Bhat1, Kenneth A. Jones2, C. Scozzie2 and Anant Agarwal3 1Center ...

Research paper thumbnail of Selective Growth of 4H-SiC on 4H-SiC Substrates using a High Temperature Mask

Materials Science Forum, 2004

Abstract. Selective growth of SiC on SiC substrate was demonstrated in a chemical vapor depositio... more Abstract. Selective growth of SiC on SiC substrate was demonstrated in a chemical vapor deposition (CVD) reactor using a new high temperature mask. Bulk 4H-SiC with 8o miscut (0001) Si-face wafers were coated with the high temperature mask and patterned using ...

Research paper thumbnail of High-voltage 4H-SiC PiN rectifiers with single-implant, multi-zone JTE termination

Proceedings of the 16th International Symposium on Power Semiconductor Devices & IC's, 2004

Abstract A novel multi-zone junction termination extension (MZJTE) is presented for high-voltage ... more Abstract A novel multi-zone junction termination extension (MZJTE) is presented for high-voltage 4H-SiC pin junction rectifiers. Unlike the conventional multi-implantation or SiC etching approaches, our new termination technique utilizes multiple masking oxide ...

Research paper thumbnail of Growth and properties of Hg 1-x Cd x Te on GaAs, with x - 0.27

J Electron Mater, 1988

The organometallic vapor phase epitaxy of HgCdTe onto (100)2-(110) GaAs substrates is described i... more The organometallic vapor phase epitaxy of HgCdTe onto (100)2-(110) GaAs substrates is described in this paper. A buffer layer of CdTe has been grown prior to the growth of HgCdTe, to take up the large lattice mismatch with the GaAs. Considerations for the thickness of this buffer layer are outlined, and it is shown by quantitative Secondary Ion Mass Spectroscopy

Research paper thumbnail of Steady-state and dynamic analyses of high-order parallel resonant convertors

Electric Power Applications Iee Proceedings B See Also Iee Proceedings Electric Power Applications, May 1, 1993

Research paper thumbnail of Electrical Characteristics and Carrier Lifetime Measurements in High Voltage 4H-SIC Pin Diodes

The key material and device parameters governing the electrical performance of high voltage 4H-Si... more The key material and device parameters governing the electrical performance of high voltage 4H-SiC PiN diodes have been investigated using experimental results and numerical simulations. Reverse recovery characteristics show an increase in both carrier lifetime and anode injection efficiency at elevated temperature. Open circuit voltage decay measurements are used to estimate carrier lifetimes (τ ≈ 0.6μs at T=25°C increasing to τ≈2μs at T=225°C) that are comparable to values measured on starting material prior to fabrication using micro-wave photoconductivity decay techniques.

Research paper thumbnail of Characteristics of Trench-Refilled 4H-SiC P-N Junction Diodes Fabricated by Selective Epitaxial Growth

Materials Science Forum, Feb 15, 2005

Abstract Selective nitrogen doping of 4H-SiC by epitaxial growth using TaC as the high temperatur... more Abstract Selective nitrogen doping of 4H-SiC by epitaxial growth using TaC as the high temperature mask has been demonstrated. Nomarski optical microscope and scanning electron microscope (SEM) were used to characterize selective growth of SiC. In addition, ...

Research paper thumbnail of A Study of Electrical Properties of Mg-Doped GaN Grown by Metalorganic Vapor Phase Epitaxy

Research paper thumbnail of Photovoltaic properties of CdTe layers grown by OMVPE

Photovoltaic characteristics of single-crystal cadmium telluride epitaxial layers grown by organo... more Photovoltaic characteristics of single-crystal cadmium telluride epitaxial layers grown by organometallic vapor phase epitaxy (OMVPE) on InSb substrates are reported. Electrical characterization of Schottky solar cells fabricated by depositing thin transparent gold shows that a hole diffusion length of 2 microns can be obtained in n-CdTe. The current flow in the p-n junction in the forward bias is determined by

Research paper thumbnail of CdTe Films Grown on InSb Substrates by Organometallic Epitaxy

MRS Proceedings, 1986

Title: CdTe films grown on InSb substrates by organometallic epitaxy. Authors: Bhat, IB; Taskar, ... more Title: CdTe films grown on InSb substrates by organometallic epitaxy. Authors: Bhat, IB; Taskar, NR; Ayers, J.; Patel, K.; Ghandhi, SK. ... Growth at 350 C resulted in the smallest x-ray rocking curve (DGRC) full width at half maximum (FWHM) of about 20 arc seconds.

Research paper thumbnail of High Voltage 4H-SiC Epitaxial Emitter BJTs using a Self-aligned Selectively Re-grown Base Contact

Hitherto, all 4H-SiC based epitaxial emitter BJTs demonstrated [1, 2], exhibit a specific on-resi... more Hitherto, all 4H-SiC based epitaxial emitter BJTs demonstrated [1, 2], exhibit a specific on-resistance (Ron,, p) value higher than the unipolar value for their drift regions. One way to reduce Ron, sp is to minimize the extrinsic base resistance by bringing the base contact ...

Research paper thumbnail of Degraded blocking performance of 4H-SiC rectifiers under high dV/dt conditions

Research paper thumbnail of Boron Filling of Deep Holes for Solid-State Neutron Detector Applications

Research paper thumbnail of Electrostatic Force Microscopy and Secondary Electron Imaging of Double Stacking Faults in Heavily n-type 4H-SiC after Oxidation

MRS Proceedings, 2003

... 742, K3.4.1 (2003). 7. BJ Skromme, MK Mikhov, L. Chen, G. Samson, R. Wang, C. Li, and I. Bhat... more ... 742, K3.4.1 (2003). 7. BJ Skromme, MK Mikhov, L. Chen, G. Samson, R. Wang, C. Li, and I. Bhat, to be published in Mater. Sci. Forum. 8. A. Henry, A. Ellison, U. Forsberg, B. Magnusson, G. Pozina and E. Janzén: Mater. Sci. Forum 389-393, 593 (2002). ...

Research paper thumbnail of Electrical Characterization of Magnesium-Doped Gallium Nitride Grown by Metalorganic Vapor Phase Epitaxy

MRS Online Proceeding Library

Research paper thumbnail of Characteristics of Trench-Refilled 4H-SiC P-N Junction Diodes Fabricated by Selective Epitaxial Growth

Materials Science Forum, 2005

Abstract Selective nitrogen doping of 4H-SiC by epitaxial growth using TaC as the high temperatur... more Abstract Selective nitrogen doping of 4H-SiC by epitaxial growth using TaC as the high temperature mask has been demonstrated. Nomarski optical microscope and scanning electron microscope (SEM) were used to characterize selective growth of SiC. In addition, ...

Research paper thumbnail of Surface studies of SiC epitaxial layers grown by chemical vapor deposition

Materials Science and Engineering: B, 2006

We have systematically carried out investigations on the growth of SiC epitaxial layers by varyin... more We have systematically carried out investigations on the growth of SiC epitaxial layers by varying C/Si ratio over the range of 0.5, 1.0, 3.0, 6.0, and 9.0 in the gas phase. The studies by an optical Nomarski microscope and an atomic force microscope revealed the growth of hillocks and nano-tube like structures for particular deposition conditions on the C-face (0 0 01) and Si-face (0 0 0 1) 4H-SiC substrates. Indeed, at extreme conditions, the triangular shape hillocks formation was found on the C-face 4H-SiC substrates whereas on the Si-face 4H-SiC substrates, the cone or dome shape structures exhibited were black in color. Several carrot-like type structures, pits, etc., were also observed on the surface of the epilayers, which affect the quality of the layers and reduce the device efficiency. At optimized conditions, the surface looked like featureless with low roughness. In addition to C/Si ratios, N 2 dopant into SiC epitaxial layers have also been studied.