Low-doped semi-insulating SIC crystals and method

The invention relates to substrates of semi-insulating silicon carbide used for semiconductor devices and a method for making the same. The substrates have a resistivity above 106 Ohm-cm, and preferably above 108 Ohm-cm, and most preferably above 109 Ohm-cm, and a capacitance below 5 pF/mm2 and pref...

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Bibliographic Details
Main Author CHEN JIHONG,ZWIEBACK ILYA,GUPTA AVINASH K.,BARRETT DONOVAN L.,HOPKINS RICHARD H.,SEMENAS EDWARD,ANDERSON THOMAS A.,SOUZIS ANDREW E
Format Patent
LanguageEnglish
Published 20.06.2007
Subjects
AFTER-TREATMENT OF SINGLE CRYSTALS OR A HOMOGENEOUSPOLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE
APPARATUS THEREFOR
BASIC ELECTRIC ELEMENTS
CHEMISTRY
CRYSTAL GROWTH
ELECTRIC SOLID STATE DEVICES NOT OTHERWISE PROVIDED FOR
ELECTRICITY
METALLURGY
PRODUCTION OF A HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITHDEFINED STRUCTURE
REFINING BY ZONE-MELTING OF MATERIAL
SEMICONDUCTOR DEVICES
SINGLE CRYSTALS OR HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITHDEFINED STRUCTURE
SINGLE-CRYSTAL-GROWTH
UNIDIRECTIONAL SOLIDIFICATION OF EUTECTIC MATERIAL ORUNIDIRECTIONAL DEMIXING OF EUTECTOID MATERIAL
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Summary:The invention relates to substrates of semi-insulating silicon carbide used for semiconductor devices and a method for making the same. The substrates have a resistivity above 106 Ohm-cm, and preferably above 108 Ohm-cm, and most preferably above 109 Ohm-cm, and a capacitance below 5 pF/mm2 and preferably below 1 pF/mm2. The electrical properties of the substrates are controlled by a small amount of added deep level impurity, large enough in concentration to dominate the electrical behavior, but small enough to avoid structural defects. The substrates have concentrations of unintentional background impurities, including shallow donors and acceptors, purposely reduced to below 5 DEG 1016 cm-3, and preferably to below 1 DEG 1016 cm-3, and the concentration of deep level impurity is higher, and preferably at least two times higher, than the difference between the concentrations of shallow acceptors and shallow donors. The deep level impurity comprises one of selected metals from the periodic groups IB, IIB, IIIB, IVB, VB, VIB, VIIB and VIIIB. Vanadium is a preferred deep level element. In addition to controlling the resistivity and capacitance, a further advantage of the invention is an increase in electrical uniformity over the entire crystal and reduction in the densityof crystal defects.
Bibliography:Application Number: CN2005823090