Semiconductor element embodying an optical coating to enhance thermal gradient zone melting processing thereof

DETAILED DESCRIPTION We claim as our invention: 1.
A semiconductor element comprising a body of semiconductor material having two major opposed surfaces being, respectively, the top and bottom surfaces thereof, a preferred crystalline material structure, a vertical axis aligned substantially parallel to a first crystal axis of the material of the body, a preferred planar crystal orientation for at least one of the major surfaces, a first type conductivity and a first level of resistivity, a first optical coating disposed on a selected portion of at least one of the two major surfaces, the optical coating having the capability of enhancing either the absorption or the re-radiation of a predetermined range of wavelength of the infrared radiation spectrum to increase the flow of heat through a predetermined portion of the body when infrared radiation from a radiant energy source impinges upon at least one of the two major opposed surfaces and is re-radiated from the opposing major surface, the first optical coating having an annular configuration when disposed on the major surface exposed directly to the radiant energy source and enhancing the absorption of a predetermined range of wavelength of the radiation spectrum, the optical coating has a thickness t.
sub.
2 which is equal to a multiple of one-fourth of the wavelength of the incident infrared radiation from a radiant energy source impinging upon the optical coating and the major surface upon which it is disposed and is expressed by the equation t.
sub.
2 = (2 n-1).
lambda.
.
sub.
s /4N.
sub.
c wherein t.
sub.
2 = thickness of the optical coating n = any positive integer greater than zero .
lambda.
.
sub.
s = the wavelength of the infrared radiation spectrum in vacuum emitted by the radiant energy source within the optical coating, and N.
sub.
c = the index of refraction of the material comprising the optical coating, the first optical coating having a disc configuration when disposed on the major surface more distant from the radiant energy source and enhancing the re-radiation of a predetermined range of the radiation spectrum from the body, and the optical coating has a preferred thickness t