Deep diode lead throughs

Claim 1

A process for making an electrically conductive lead through region in a semiconductor device comprising the process steps of: a. selecting a body of semiconductor material so that the body has two major opposed surfaces, at least one of the major surfaces having a preferred planar crystal structure orientation which is one selected from the group consisting of (100), (110) and (111), a vertical axis which is substantially aligned in parallel with a first preferred crystal axis of the material of the body, a preferred level of resistivity, and a preferred type of conductivity; b. vapor depositing at least one mass of a selective metal on a selective portion of the major surface of the body of semiconductor material having the preferred planar crystal structure orientation; c. heating the body and each mass of metal to an elevated temperature sufficient to form a melt of metal-rich semiconductor material of the body for each mass, the melt comprising the vapor deposited metal and a portion of the material of the body in contact therewith; d. establishing a temperature gradient in the body substantially parallel with the vertical axis and the first preferred crystal axis of the body e. migrating each melt of metal-rich semiconductor material through the body at a predetermined elevated temperature along a path substantially parallel with the established temperature gradient in the direction of the higher temperature of the temperature gradient from the one major surface to, and terminating in, the other of the two major opposed surfaces to form in situ a region of recrystallized semiconductor material of the body having two opposed end surfaces, each being coextensive with a respective one of the two opposed major surfaces and having a predetermined level of concentration of the metal of the melt distributed substantially uniformly throughout the entire region as determined by the solid solubility limit of that metal in that semiconductor material at that predetermined elevated temperature of migration, the metal comprising at least one dopant impurity material therein to impart thereto a predetermined second and opposite type conductivity than that of the material of the body and a predetermined level of resistivity to the region sufficient to render it electrically conductive, and f. forming a P-N junction at the contiguous surfaces of the material of each region of recrystallized semiconductor material and that of the body.