Formation of grain boundary photoorienter by electrolytic etching

Claim 1

A PROESS FOR ETCHING A SEMICONDUCTOR CELL ALONG A GRAIN BOUNDARY EXTENDING THROUGH THE CELL FROM A FIRST SURFACE TO A SECOND SURFACE THEREOF, SAID CELL INCLUDING HOMOGENEOUS, GENERALLY SINGLE CRYSTALLINE MATERIAL ON OPPOSITE SIDES OF SAID GRAIN BOUNDARY, WHICH COMPRISES THE STEPS OF PLACING SAID SECOND SURFACE OF SAID CELL IN CONTACT WITH AN ELECTROLYTIC ETCHING SOLUTION, APPLYING A SUBSTANTIALLY CONSTANT ELECTRIC POTENTIAL ACROSS SAID FIRST SURFACE OF SAID CELL ON EACH SIDE OF SAID GRAIN BOUNDARY AND SAID ELECTROLYTIC SOLUTION SO THAT AN ELECTRIC POTENTIAL IS MAINTAINED ACROSS SAID ELECTROLYTIC SOLUTION AND SAID SECOND SURFACE OF SAID CELL, AND THEN IRRADIATING SAID FIRST SURFACE TO INCREASE THE GENERATION OF CURRENT CARRIES ALONG SAID GRAIN BOUNDARY TO EACH A GROOVE IN SAID CELL ALONG SAID GRAIN BOUNDARY IN CONTACT WITH SAID ELECTROLYTIC SOLUTION.