Current isolation means for integrated power devices

Claim 1

An integrated semiconductor power device comprising: a body of semiconductor material having two major opposed surfaces which are, respectively, the top and bottom surfaces thereof, a predetermined type conductivity, a vertical axis which is aligned substantially parallel with a first preferred axis of the material of the body, and a first predetermined carrier lifetime; at least one of the two major opposed surfaces having a preferred planar crystal orientation which is one selected from the group consisting of (100), (110) and (111); at least two mutually adjacent semiconductor devices formed in the body and in abutting contact with one another; each device including at least two regions of alternate and opposite type conductivity; a P-N junction formed by the contiguous surfaces of the material of each abutting pair of regions of opposite type conductivity in each device; a portion of at least one P-N junction in each of the devices is aligned parallel with the two opposed major surfaces of the body; a first region of recrystallized semiconductor material disposed in the body, extending entirely through the body, and terminating in, the two opposed major surfaces of the body, the first region having a vertical axis which is aligned substantially parallel with the first preferred axis of the material of the body and the vertical axis of the body, and a second predetermined carrier lifetime, and the first region includes a predetermined portion of the material of each of the mutually adjacent devices in abutting contact with each other; the first region being oriented in the body along a preferred wire direction which is aligned substantially parallel with a second preferred axis of the material of the body; a first array of columnar regions of recrystallized semiconductor material disposed in the body and so arranged as to extend entirely through a predetermined portion of one of the devices of the body from one opposed major surface to the other, each columnar region having a longitudinal axis aligned substantially parallel with each of the other longitudinal axes and with the first preferred crystal axis of the body and a third predetermined carrier lifetime; a second array of columnar regions of recrystallized semiconductor material disposed in the body and so arranged as to extend entirely through a predetermined portion of the other one of the devices of the body from one opposed major surface to the other, each columnar region having a longitudinal axis aligned substantially parallel with each of the other longitudinal axes and with the first preferred crystal axis of the body and a fourth predetermined carrier lifetime, and each first region and columnar region of recrystallized semiconductor material is formed in situ in the body by the migration of a respective melt of metal-rich semiconductor material of the region of the body through which it is migrated by a thermal gradient zone melting process at a predetermined elevated temperature along a thermal gradient established substantially parallel with the first crystal axis of the material of the body and has a predetermined level of concentration of the metal of the melt, as determined by the solid solubility limit of that metal in that semiconductor material at that predetermined elevated temperature of migration, the metal being distributed substantially uniformly throughout the entire region and including at least one deep level impurity material suitable for imparting the predetermined carrier lifetime thereto.