Electrolytic production of standard oxide layer on silicon bodies - using focussed laser beam to heat areas where oxide is to be produced

Method of producing a structural oxide coating on a silicon surface in which the surface is contacted with an aq. light permeable electrolyte. The silicon surface is connected to the position pole of a DC source and a passive electrode is connected to the negative pole. The area where an oxide layer is to be produced is then heated by a focussed laser beam whose light is chosen so that it can pass through the electrolyte without being absorbed. USE/ADVANTAGE - Producing pn junctions in silicon crystals. The thermal stress introduced into the body of the crystal is held at a minimum and the standard oxide layer produced may be thick.