Anneal of Oxide Damage by Light
Original Publication Date: 1980-Sep-01
Included in the Prior Art Database: 2005-Feb-13
Exposure of FET/CCD device wafers to penetrating radiation (such as E-beam, X-ray or hard UV light) has been demonstrated to create damage sites within the insulating medium under the gate electrodes. This damage (in the form of fixed charge, surface state, neutral traps, etc.) manifests itself in the form of a voltage shift in the threshold of the device. It has been determined [1,2] that this damage can be removed by annealing the wafers at relatively high temperatures (optimum being between 600 degrees C and 900 degrees C). The present metallurgy will not tolerate temperatures in excess of 450 degrees C due to aluminum penetration problems. As a result, other techniques for damage removal, such as RF annealing, have been sought.