Screw DIS location!

I prefer to keep this weblog's subject matter of a light and airy nature, like a spring breeze through my unzipped trousers while in the Swiss Alps (at least, I imagine it's like that). But if I see something I'm strongly against I will speak my mind. Today I feel the dire need to address a most serious topic: the presence of screw dislocations in the surfaces of Silicon Carbide (SiC) wafers. SiC is a wide bandgap material and thus intriguing for use with electronic applications. For instance, RAM chips produced from SiC would be nonvolatile and could eliminate the need for permanent storage media such as hard disks. Though twinned structure defects can occasionally occur during the epitaxial growth process they are not the main issue. Physical vapor transport (PVT) is the usual technique for growing boules of SiC from initial seed crystals. During this growth, point defects on the surface eventually converge forming super-screw dislocations that result in micropipes. These micropipes have an adverse effect on the wafer's high-voltage electrical properties. How to eliminate these defects? How?! Oh the humanity.