Process for the manufacture of vertical P-N junctions in the pulling of silicon from a silicon melt

Claim 1

In a process for the manufacture of p-n junctions in the pulling of silicon ribbons, polygons or tubes from a silicon melt, the improvement comprising: adding to the silicon melt both dopants that act as acceptors and dopants that act as donors, of which the effective distribution coefficients k Aeff (v h ) and k Deff (v h ) at a high crystal growht rate v h and the effective distribution coefficients k Aeff (v h ) and k Deff (v h ) at a low crystal growth rate v n satisfy the condition ##EQU9## wherein, generally, v h is a crystal growth rate higher than the mean pulling speed and v n is a crystal growth rate lower than the mean pulling speed; pulling silicon from the melt at a mean pulling speed of from 6 to 120 mm/min.; and periodically varying the crystal growth rate during the pulling operation between a low rate v n and a high rate v h so that the total length of each p- and n-conductive zone in the crystallized silicon is from 5 to 2000 μm.