Method of making a semiconductor chip

A method of fabricating an optically-triggered silicon controlled rectifier (SCR) device comprising:

• providing an N type substrate having an upper surface, a lower surface and opposed side edges;
• diffusing a first P+ layer into the upper surface of said substrate;
• diffusing an N+ layer into an upper surface of said P+ layer;
• forming a permeable oxide layer on a portion of said first P+ layer;
• depositing a cathode contact on said N+ layer;
• diffusing a second P+ layer into said lower surface of said substrate;
• depositing an anode contact on said second P+ layer;
• forming a pedestal on a surface of a lead frame;
• and
• mounting said substrate on said pedestal with said anode contact fixed to said pedestal such that said side edges extend beyond said pedestal and are spaced from said lead frame.