Abstract: A high quality single crystal wafer of SiC is disclosed. The wafer has a diameter of at least about 3 inches (75 mm) and at least one continuous square inch (6.25 cm2) of surface area that has a basal plane dislocation volume density of less than about 500 cm?2 for a 4 degree off-axis wafer.

Abstract: A high quality single crystal wafer of SiC is disclosed having a diameter of at least about 3 inches and a 1 c screw dislocation density of less than about 2000 cm?2.

Abstract: A silicon carbide seeded sublimation growth system and associated method are disclosed. The system includes a crucible, a silicon carbide source composition in the crucible, a seed holder in the crucible, a silicon carbide seed crystal on the seed holder, means for creating a major thermal gradient in the crucible that defines a major growth direction between the source composition and the seed crystal for encouraging vapor transport between the source composition and the seed crystal, and the seed crystal being positioned on the seed holder with the macroscopic growth surface of the seed crystal forming an angle of between about 70° and 89.5° degrees relative to the major thermal gradient and the major growth direction and with the crystallographic orientation of the seed crystal having the c-axis of the crystal forming an angle with the major thermal gradient of between about 0° and 2°.

Abstract: A single polytype single crystal silicon carbide wafer is disclosed having a diameter greater than three inches and less than five inches, resistivity greater than 10,000 ohm-cm, a micropipe density less than 200 cm?2, and a combined concentration of shallow level dopants less than 5E16 cm?3.

Abstract: A mobile telephone, or personal communication services subscriber who wishes directory assistance services is connected in the conventional manner to an operator who identifies a destination telephone number desired by the subscriber. As known in the prior art, the operator then initiates a call connecting the subscriber to the destination telephone number. In a preferred embodiment, the operator locates a desired destination telephone number in a computer database, and can select automatic dialing of the located number. Further, rather than dropping all further involvement with the call, the preferred embodiment of the present invention continually monitors the connection thereby established for a predetermined DTMF signal issued by the customer, such as that obtained by pressing the “?” button. If such a signal is detected, the customer is transferred to a directory assistance operator, who can then provide whatever further assistance is needed (e.g., providing further directory assistance).