Don Barrett - Academia.edu (original) (raw)
Papers by Don Barrett
Journal of Crystal Growth, 1991
Silicon carbide is an attractive candidate for high power and high temperature electronics due to... more Silicon carbide is an attractive candidate for high power and high temperature electronics due to its inherent high thermal cnductivity, large saturated drift velocity, high breakdown strength and large bandgap. A review of the material properties which i~fluence semiconductor device characteristics is presented, and recent advances in crystal growth technology leading to the reparation of 25 mm and larger wafers for "silicon-like" device fabrication processes are reviewed. A sublimation vapor transport 9stem is described and preliminary results on growth of 6H-S1C boules are presented.
Journal of crystal …, 1991
Silicon carbide is an attractive candidate for high power and high temperature electronics due to... more Silicon carbide is an attractive candidate for high power and high temperature electronics due to its inherent high thermal cnductivity, large saturated drift velocity, high breakdown strength and large bandgap. A review of the material properties which i~fluence semiconductor device characteristics is presented, and recent advances in crystal growth technology leading to the reparation of 25 mm and larger wafers for "silicon-like" device fabrication processes are reviewed. A sublimation vapor transport 9stem is described and preliminary results on growth of 6H-S1C boules are presented.
Applied Physics Letters, 1998
A process for growing micropipe-free single crystals has been developed by using the modified Lel... more A process for growing micropipe-free single crystals has been developed by using the modified Lely method. The process parameters were kept close to thermal equilibrium. The maximum average thermal gradient inside the growth furnace leading to micropipe-free growth was 5 K/cm. A gradient of 7.5 K/cm already resulted in a strong defect formation and produced a high density of micropipes (>200 cm−2). The highest achieved growth rate providing micropipe-free growth was 0.27 mm/h. For the employed parameter range, 6H-SiC single boule crystals were grown on both the C face and the Si face of 6H-SiC Lely platelets. The grown crystals are electrically and optically characterized.
Abstract : The loss through recombination of minority carriers generated deep within a silicon so... more Abstract : The loss through recombination of minority carriers generated deep within a silicon solar cell is a limitation on the efficiency and radiation resistance of present devices. In this work the authors have explored the potential of multijunction silicon solar cells prepared by diffusion and epitaxial techniques for improved efficiency and radiation resistance. Two-junction diffused cell structures were found to offer improved performance for very thin wafers. (Author)
: The techniques for producing n(+)-p-n(+) structures in gallium arsenides are described. Evaluat... more : The techniques for producing n(+)-p-n(+) structures in gallium arsenides are described. Evaluation of the surface state densities of anodic oxide on gallium arsenide show minima at about mid gap of 2 times 10 to the 11th power eV sq.cm. These densities are affected by annealing conditions and their measurement by sweep time. Recommendations for future work include the use of indium phosphide as the semiconductor. (Author)
: Indium doping at 5 x 10 to the 19th power/cc was found to be optimum for the growth of low-disl... more : Indium doping at 5 x 10 to the 19th power/cc was found to be optimum for the growth of low-dislocation GaAs crystals, and to avoid constitutional supercooling effects. Dislocation etch pit densities of near 200/cc were measured in the central region of In-doped crystals, increasing to above 1000/sq cm in the peripheral regions. Based on the concept that dislocations are generated to relieve excess thermoelastic stress, a preliminary thermal model was used to design a hot zone shield to reduce thermal gradients during growth. An optimum combination of indium-doping, reduced thermal gradient growth, and appropriate growth parameters are expected to yield completely dislocation-free GaAs crystals. A FET metrology mask has been fabricated and preliminary FET device Fabricaion begun, for evaluation of the effects of dislocations on FET device parameters. Twenty state-of-the-art, low dislocation, indium-doped GaAs wafers were delivered to the contractor for DARPA-related program evaluat...
Semiconductors and Semimetals, 1984
Publisher Summary This chapter discusses the establishment of a reproducible gallium arsenide (Ga... more Publisher Summary This chapter discusses the establishment of a reproducible gallium arsenide (GaAs) materials base to realize the full potential of direct ion implantation as a reliable, cost-effective fabrication technology of high-performance GaAs metal–semiconductor field effect transistor (MESFET) devices and integrated circuits (IC). The considerable efforts directed at improving basic GaAs materials and processes result from the strong interdependence of high-frequency GaAs circuit performance upon substrate quality. Many of the conventional wafer preparation techniques used today in silicon have been applied on a laboratory scale to large liquid-encapsulated Czochralski (LEC)-grown GaAs crystals. The low-breakage processing of GaAs demands the development of special handling techniques based on the automated cassette and wafer transport methods that are being utilized in silicon IC manufacturing.
Semi-Insulating III–V Materials, 1980
The growth of 2 and 3 inch diameter, oriented semi-insulating GaAs crystals of improved purity by... more The growth of 2 and 3 inch diameter, oriented semi-insulating GaAs crystals of improved purity by liquid encapsulated Czochralski (LEC) growth from silicon-free, pyrolytic boron nitride (PBN) crucibles in a high pressure Melbourn crystal puller, is described. Undoped and Cr-doped LEC GaAs crystals pulled from PBN crucibles exhibit bulk resistivities in the 107–108 and 108–109 ohm-cm ranges, respectively. High sensitivity SIMS demonstrates that GaAs crystals grown from PBN crucibles contain residual silicon concentrations in the low 1015 cm-3 range, compared to concentrations up to the 1016 cm-3 range for growths in silica containers. The residual chromium content in LEC/PBN-grown crystals is below the l05 cm-3 range.
This paper reports the progress that has been made in the development of large periphery S-band G... more This paper reports the progress that has been made in the development of large periphery S-band GaAs Schottky barrier field-effect transistors using two different fabrication techniques. One process relies on the conventional photolithographic alignment of a gate electrode inside a source-drain spacing. The other method is a self-aligned technique which involves plating both the drain and source metal contacts to control the gate length. The transistors fabricated using these techniques are referred to as RAGFET (Realigned-Gate-FET) and SAGFET (Selfaligned-Gate-FET) devices, respectively.
physica status solidi (a), 2000
Bulk single crystals of the 15R-polytype of SiC have been grown by the sublimation physical-vapor... more Bulk single crystals of the 15R-polytype of SiC have been grown by the sublimation physical-vapor-transport technique. 15R-SiC crystal growth was stabilized on a 15R-SiC seed using near-thermal-equilibrium growth conditions and a stoichiometric SiC sublimation source material. The polarity of the seed surface is shown to be an important factor in preparation of the 15R-polytype. The dual seed method (simultaneous growth on the Si- and C-face) was employed to demonstrate that 15R-polytype growth occurred only on the Si-face, while 6H- and 4H-polytype growth occurred on the C-face. The incorporation of nitrogen donors and boron acceptors was also shown to be a function of seed polarity, with nitrogen incorporation on the C-face two times that on the Si-face, and boron incorporation on the C-face one-half that on the Si-face.
Journal of The Electrochemical Society, 1971
The temperature field and heat flow about the solidification interface of web crystals was modifi... more The temperature field and heat flow about the solidification interface of web crystals was modified by use of shaped radiation sinks. As a result, web was grown as wide as 3 cm and flat to less than 2.5 µm in 100 µm thick sheet. A qualitative extension of thermal models in dendrite growth applied to web morphology satisfactorily explains the experimentally observed results.
Journal of Crystal Growth, 1993
We have grown 6H-polytype SiC single crystal boules up to 60 mm in diameter by the physical vapor... more We have grown 6H-polytype SiC single crystal boules up to 60 mm in diameter by the physical vapor transport process at 2300°C. [0001] oriented substrate wafers prepared from these undoped crystals exhibit resistivities of up to 105 ~ cm and etch pit defect densities of 104-105 cm-2. Epitaxially-grown microwave MESFET structures exhibit 5 GHz cutoff frequency; the highest reported to date.
Journal of Crystal Growth, 1970
Abstract Because it is not wet by molten silicon (the contact angle is (87±5°), quartz is commonl... more Abstract Because it is not wet by molten silicon (the contact angle is (87±5°), quartz is commonly used for growth of crystals of this semiconductor. In growing silicon web from axially symmetric quartz crucibles, we have found melts that are far from round. As the melt level falls during growth, the melts may spontaneously move, changing their shape with great vigor. The motion spoils crystal surface quality and often terminates crystal growth entirely. Some explanations are offered for this behavior.
Journal of Crystal Growth, 1984
Diamond and Related Materials, 1997
The dual-seed-crystal method is developed and used to study the growth of 4H-and GH-SiC boule cry... more The dual-seed-crystal method is developed and used to study the growth of 4H-and GH-SiC boule crystals by varying particular growth parameters, e.g. the distance between the growth front and the source material and the face polarity of the seeds. A range of values is elaborated for a series of growth parameters, which leads to the growth of single crystals. The grown Sic crystals are electrically and optically characterized. 0 1997 Elsevier Science S.A.
Journal of Crystal …, 1984
Diamond and Related Materials, 1997
The dual-seed-crystal method is developed and used to study the growth of 4H-and GH-SiC boule cry... more The dual-seed-crystal method is developed and used to study the growth of 4H-and GH-SiC boule crystals by varying particular growth parameters, e.g. the distance between the growth front and the source material and the face polarity of the seeds. A range of values is elaborated for a series of growth parameters, which leads to the growth of single crystals. The grown Sic crystals are electrically and optically characterized. 0 1997 Elsevier Science S.A.
Journal of crystal …, 1993
We have grown 6H-polytype SiC single crystal boules up to 60 mm in diameter by the physical vapor... more We have grown 6H-polytype SiC single crystal boules up to 60 mm in diameter by the physical vapor transport process at 2300°C. [0001] oriented substrate wafers prepared from these undoped crystals exhibit resistivities of up to 105 ~ cm and etch pit defect densities of 104-105 cm-2. Epitaxially-grown microwave MESFET structures exhibit 5 GHz cutoff frequency; the highest reported to date.
Abstract Summary form only given. The authors describe record-setting 5-GHz SiC MESFET performanc... more Abstract Summary form only given. The authors describe record-setting 5-GHz SiC MESFET performance and the effects of device design on achieving these results. Bulk growth of 6H-SiC was performed using a physical vapor transport process, and the resultant undoped ...
Journal of Crystal Growth, 1991
Silicon carbide is an attractive candidate for high power and high temperature electronics due to... more Silicon carbide is an attractive candidate for high power and high temperature electronics due to its inherent high thermal cnductivity, large saturated drift velocity, high breakdown strength and large bandgap. A review of the material properties which i~fluence semiconductor device characteristics is presented, and recent advances in crystal growth technology leading to the reparation of 25 mm and larger wafers for "silicon-like" device fabrication processes are reviewed. A sublimation vapor transport 9stem is described and preliminary results on growth of 6H-S1C boules are presented.
Journal of crystal …, 1991
Silicon carbide is an attractive candidate for high power and high temperature electronics due to... more Silicon carbide is an attractive candidate for high power and high temperature electronics due to its inherent high thermal cnductivity, large saturated drift velocity, high breakdown strength and large bandgap. A review of the material properties which i~fluence semiconductor device characteristics is presented, and recent advances in crystal growth technology leading to the reparation of 25 mm and larger wafers for "silicon-like" device fabrication processes are reviewed. A sublimation vapor transport 9stem is described and preliminary results on growth of 6H-S1C boules are presented.
Applied Physics Letters, 1998
A process for growing micropipe-free single crystals has been developed by using the modified Lel... more A process for growing micropipe-free single crystals has been developed by using the modified Lely method. The process parameters were kept close to thermal equilibrium. The maximum average thermal gradient inside the growth furnace leading to micropipe-free growth was 5 K/cm. A gradient of 7.5 K/cm already resulted in a strong defect formation and produced a high density of micropipes (>200 cm−2). The highest achieved growth rate providing micropipe-free growth was 0.27 mm/h. For the employed parameter range, 6H-SiC single boule crystals were grown on both the C face and the Si face of 6H-SiC Lely platelets. The grown crystals are electrically and optically characterized.
Abstract : The loss through recombination of minority carriers generated deep within a silicon so... more Abstract : The loss through recombination of minority carriers generated deep within a silicon solar cell is a limitation on the efficiency and radiation resistance of present devices. In this work the authors have explored the potential of multijunction silicon solar cells prepared by diffusion and epitaxial techniques for improved efficiency and radiation resistance. Two-junction diffused cell structures were found to offer improved performance for very thin wafers. (Author)
: The techniques for producing n(+)-p-n(+) structures in gallium arsenides are described. Evaluat... more : The techniques for producing n(+)-p-n(+) structures in gallium arsenides are described. Evaluation of the surface state densities of anodic oxide on gallium arsenide show minima at about mid gap of 2 times 10 to the 11th power eV sq.cm. These densities are affected by annealing conditions and their measurement by sweep time. Recommendations for future work include the use of indium phosphide as the semiconductor. (Author)
: Indium doping at 5 x 10 to the 19th power/cc was found to be optimum for the growth of low-disl... more : Indium doping at 5 x 10 to the 19th power/cc was found to be optimum for the growth of low-dislocation GaAs crystals, and to avoid constitutional supercooling effects. Dislocation etch pit densities of near 200/cc were measured in the central region of In-doped crystals, increasing to above 1000/sq cm in the peripheral regions. Based on the concept that dislocations are generated to relieve excess thermoelastic stress, a preliminary thermal model was used to design a hot zone shield to reduce thermal gradients during growth. An optimum combination of indium-doping, reduced thermal gradient growth, and appropriate growth parameters are expected to yield completely dislocation-free GaAs crystals. A FET metrology mask has been fabricated and preliminary FET device Fabricaion begun, for evaluation of the effects of dislocations on FET device parameters. Twenty state-of-the-art, low dislocation, indium-doped GaAs wafers were delivered to the contractor for DARPA-related program evaluat...
Semiconductors and Semimetals, 1984
Publisher Summary This chapter discusses the establishment of a reproducible gallium arsenide (Ga... more Publisher Summary This chapter discusses the establishment of a reproducible gallium arsenide (GaAs) materials base to realize the full potential of direct ion implantation as a reliable, cost-effective fabrication technology of high-performance GaAs metal–semiconductor field effect transistor (MESFET) devices and integrated circuits (IC). The considerable efforts directed at improving basic GaAs materials and processes result from the strong interdependence of high-frequency GaAs circuit performance upon substrate quality. Many of the conventional wafer preparation techniques used today in silicon have been applied on a laboratory scale to large liquid-encapsulated Czochralski (LEC)-grown GaAs crystals. The low-breakage processing of GaAs demands the development of special handling techniques based on the automated cassette and wafer transport methods that are being utilized in silicon IC manufacturing.
Semi-Insulating III–V Materials, 1980
The growth of 2 and 3 inch diameter, oriented semi-insulating GaAs crystals of improved purity by... more The growth of 2 and 3 inch diameter, oriented semi-insulating GaAs crystals of improved purity by liquid encapsulated Czochralski (LEC) growth from silicon-free, pyrolytic boron nitride (PBN) crucibles in a high pressure Melbourn crystal puller, is described. Undoped and Cr-doped LEC GaAs crystals pulled from PBN crucibles exhibit bulk resistivities in the 107–108 and 108–109 ohm-cm ranges, respectively. High sensitivity SIMS demonstrates that GaAs crystals grown from PBN crucibles contain residual silicon concentrations in the low 1015 cm-3 range, compared to concentrations up to the 1016 cm-3 range for growths in silica containers. The residual chromium content in LEC/PBN-grown crystals is below the l05 cm-3 range.
This paper reports the progress that has been made in the development of large periphery S-band G... more This paper reports the progress that has been made in the development of large periphery S-band GaAs Schottky barrier field-effect transistors using two different fabrication techniques. One process relies on the conventional photolithographic alignment of a gate electrode inside a source-drain spacing. The other method is a self-aligned technique which involves plating both the drain and source metal contacts to control the gate length. The transistors fabricated using these techniques are referred to as RAGFET (Realigned-Gate-FET) and SAGFET (Selfaligned-Gate-FET) devices, respectively.
physica status solidi (a), 2000
Bulk single crystals of the 15R-polytype of SiC have been grown by the sublimation physical-vapor... more Bulk single crystals of the 15R-polytype of SiC have been grown by the sublimation physical-vapor-transport technique. 15R-SiC crystal growth was stabilized on a 15R-SiC seed using near-thermal-equilibrium growth conditions and a stoichiometric SiC sublimation source material. The polarity of the seed surface is shown to be an important factor in preparation of the 15R-polytype. The dual seed method (simultaneous growth on the Si- and C-face) was employed to demonstrate that 15R-polytype growth occurred only on the Si-face, while 6H- and 4H-polytype growth occurred on the C-face. The incorporation of nitrogen donors and boron acceptors was also shown to be a function of seed polarity, with nitrogen incorporation on the C-face two times that on the Si-face, and boron incorporation on the C-face one-half that on the Si-face.
Journal of The Electrochemical Society, 1971
The temperature field and heat flow about the solidification interface of web crystals was modifi... more The temperature field and heat flow about the solidification interface of web crystals was modified by use of shaped radiation sinks. As a result, web was grown as wide as 3 cm and flat to less than 2.5 µm in 100 µm thick sheet. A qualitative extension of thermal models in dendrite growth applied to web morphology satisfactorily explains the experimentally observed results.
Journal of Crystal Growth, 1993
We have grown 6H-polytype SiC single crystal boules up to 60 mm in diameter by the physical vapor... more We have grown 6H-polytype SiC single crystal boules up to 60 mm in diameter by the physical vapor transport process at 2300°C. [0001] oriented substrate wafers prepared from these undoped crystals exhibit resistivities of up to 105 ~ cm and etch pit defect densities of 104-105 cm-2. Epitaxially-grown microwave MESFET structures exhibit 5 GHz cutoff frequency; the highest reported to date.
Journal of Crystal Growth, 1970
Abstract Because it is not wet by molten silicon (the contact angle is (87±5°), quartz is commonl... more Abstract Because it is not wet by molten silicon (the contact angle is (87±5°), quartz is commonly used for growth of crystals of this semiconductor. In growing silicon web from axially symmetric quartz crucibles, we have found melts that are far from round. As the melt level falls during growth, the melts may spontaneously move, changing their shape with great vigor. The motion spoils crystal surface quality and often terminates crystal growth entirely. Some explanations are offered for this behavior.
Journal of Crystal Growth, 1984
Diamond and Related Materials, 1997
The dual-seed-crystal method is developed and used to study the growth of 4H-and GH-SiC boule cry... more The dual-seed-crystal method is developed and used to study the growth of 4H-and GH-SiC boule crystals by varying particular growth parameters, e.g. the distance between the growth front and the source material and the face polarity of the seeds. A range of values is elaborated for a series of growth parameters, which leads to the growth of single crystals. The grown Sic crystals are electrically and optically characterized. 0 1997 Elsevier Science S.A.
Journal of Crystal …, 1984
Diamond and Related Materials, 1997
The dual-seed-crystal method is developed and used to study the growth of 4H-and GH-SiC boule cry... more The dual-seed-crystal method is developed and used to study the growth of 4H-and GH-SiC boule crystals by varying particular growth parameters, e.g. the distance between the growth front and the source material and the face polarity of the seeds. A range of values is elaborated for a series of growth parameters, which leads to the growth of single crystals. The grown Sic crystals are electrically and optically characterized. 0 1997 Elsevier Science S.A.
Journal of crystal …, 1993
We have grown 6H-polytype SiC single crystal boules up to 60 mm in diameter by the physical vapor... more We have grown 6H-polytype SiC single crystal boules up to 60 mm in diameter by the physical vapor transport process at 2300°C. [0001] oriented substrate wafers prepared from these undoped crystals exhibit resistivities of up to 105 ~ cm and etch pit defect densities of 104-105 cm-2. Epitaxially-grown microwave MESFET structures exhibit 5 GHz cutoff frequency; the highest reported to date.
Abstract Summary form only given. The authors describe record-setting 5-GHz SiC MESFET performanc... more Abstract Summary form only given. The authors describe record-setting 5-GHz SiC MESFET performance and the effects of device design on achieving these results. Bulk growth of 6H-SiC was performed using a physical vapor transport process, and the resultant undoped ...