United States of America as Represented by the Administrator of Nasa

Ohio Aerospace Institute

The United States of America as Represented by the Administrator of the

The United States of America as Represented by the United States

The United States of America as Represented by the Administrator

The United States of America as Represented by the Administrator of

J Anthony Powell

Philip G Neudeck

David J Larkin

Lawrence G Matus

David James Spry

Phillip B Abel

Andrew J Trunek

Herbert A Will

A method and the benefits resulting from the product thereof are disclosed for the growth of large, low-defect single-crystals of tetrahedrally-bonded crystal materials. The process utilizes a uniquely designed crystal shape whereby the direction of rapid growth is parallel to a preferred crystal direction. By establishing several regions of growth, a large single crystal that is largely defect-free can be grown at high growth rates. This process is particularly suitable for producing products for wide-bandgap semiconductors, such as SiC, GaN, AlN, and diamond. Large low-defect single crystals of these semiconductors enable greatly enhanced performance and reliability for applications involving high power, high voltage, and/or high temperature operating conditions.

Method for the growth of large low-defect single crystals

Methods are disclosed that provide for structures and techniques for the fabrication of ordered arrangements of crystallographically determined nanometer scale steps on single crystal substrates, particularly SiC. The ordered nanometer scale step structures are produced on the top surfaces of mesas by a combination of growth and etching processes. These structures, sometimes referred to herein as artifacts, are to enable step-height calibration, particularly suitable for scanning probe microscopes and profilometers, from less than one nanometer (nm) to greater than 10 nm, with substantially no atomic scale roughness of the plateaus on either side of each step.

Method for the production of nanometer scale step height reference specimens

The present invention is related to a method that enables and improves wide bandgap homoepitaxial layers to be grown on axis single crystal substrates, particularly SiC. The lateral positions of the screw dislocations in epitaxial layers are predetermined instead of random, which allows devices to be reproducibly patterned to avoid performance degrading crystal defects normally created by screw dislocations.

Lateral movement of screw dislocations during homoepitaxial growth and devices yielded therefrom free of the detrimental effects of screw dislocations

A method is disclosed for growing high-quality low-defect crystal films heteroepitaxially on substrates that are different than the crystal films. The growth of the first two heteroepitaxial bilayers is performed on a first two-dimensional nucleate island before a second growth of two-dimensional nucleation is allowed to start. The method is particularly suited for the growth of 3C-SiC, 2H-AlN, or 2H-GaN on 6H-SiC, 4H-SiC, or silicon substrates.

Method for growing low-defect single crystal heteroepitaxial films

A method for growing arrays of large-area device-size films of step-free (i.e., atomically flat) SiC surfaces for semiconductor electronic device applications is disclosed. This method utilizes a lateral growth process that better overcomes the effect of extended defects in the seed crystal substrate that limited the obtainable step-free area achievable by prior art processes. The step-free SiC surface is particularly suited for the heteroepitaxial growth of 3C (cubic) SiC, AlN, and GaN films used for the fabrication of both surface-sensitive devices (i.e., surface channel field effect transistors such as HEMT's and MOSFET's) as well as high-electric field devices (pn diodes and other solid-state power switching devices) that are sensitive to extended crystal defects.

Methods for growth of relatively large step-free SiC crystal surfaces

A method of growing atomically-flat surfaces and high quality low-defect crystal films of semiconductor materials and fabricating improved devices thereon. The method is also suitable for growing films heteroepitaxially on substrates that are different than the film. The method is particularly suited for growth of elemental semiconductors (such as Si), compounds of Groups III and V elements of the Periodic Table (such as GaN), and compounds and alloys of Group IV elements of the Periodic Table (such as SiC).

Method for growth of crystal surfaces and growth of heteroepitaxial

A method of growing atomically-flat surfaces and high-quality low-defect crystal films of polytypic compounds heteroepitaxially on polytypic compound substrates that are different than the crystal film. The method is particularly suited for the growth of 3C-SiC, 2H-AlN, and 2H-GaN on 6H-SiC.

A method of controlling the amount of impurity incorporation in a crystal grown by a chemical vapor deposition process. Conducted in a growth chamber, the method includes the controlling of the concentration of the crystal growing components in the growth chamber to affect the demand of particular growth sites within the growing crystal thereby controlling impurity incorporation into the growth sites.

Compound semi-conductors and controlled doping thereof

Compound semiconductor and controlled doping thereof

The invention is a method for growing homoepitaxial films of SiC on low-tilt-angle vicinal (0001) SiC wafers. The invention proposes and teaches a new theoretical model for the homoepitaxial growth of SiC films on (0001) SiC substrates. The inventive method consists of (1) preparing the growth surface of SiC wafers slightly off-axis (from less than 0.1.degree. to 6.degree.) from the (0001) plane, (2) subjecting the growth surface to a suitable etch, and then (3) growing the homoepitaxial film using conventional SiC growth techniques.

Process for the homoepitaxial growth of single-crystal silicon carbide

Sections are cut from a SiC platelet such that the sections have a-faces parallel to the c-axis of the SiC platelet. The sections serve as substrates for the growth of SiC layers by attaching the substrates to a body which is then placed in a chamber and the chamber evacuated. Hydrogen is then admitted, and the body on which the substrates are mounted is heated to produce a temperature profile such that the subsequent admission of a carbon containing chlorosilane gas or a mixture of a chlorosilane gas and a hydrocarbon gas will cause free silicon to be deposited at one end of the body while SiC crystals grow on the substrates which are in a preferred temperature range. Dopant gases, either p-type or n-type, can be admitted with the chlorosilane or hydrocarbon gas to produce the desired type of semiconductor.

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North Olmsted, OH, United States of America

J Anthony Powell