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Removal of Implant Damage

IP.com Disclosure Number: IPCOM000085248D
Original Publication Date: 1976-Mar-01
Included in the Prior Art Database: 2005-Mar-02
Document File: 1 page(s) / 12K

Publishing Venue

IBM

Related People

Bogardus, EH: AUTHOR [+2]

Abstract

High dosage shallow implants in SiO(2)-Si structures can cause severe device problems, such as early breakdowns and high-leakage currents. This electrical degradation cannot be removed by conventional annealing in nitrogen or argon without significant movement of the implant boundaries. Past processing has required silicon dioxide removal and silicon dioxide regrowth. Oxide removal places severe limitations on device fabrication, where minimum temperature-time cycles are required to prevent junction movement.

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Removal of Implant Damage

High dosage shallow implants in SiO(2)-Si structures can cause severe device problems, such as early breakdowns and high-leakage currents. This electrical degradation cannot be removed by conventional annealing in nitrogen or argon without significant movement of the implant boundaries. Past processing has required silicon dioxide removal and silicon dioxide regrowth. Oxide removal places severe limitations on device fabrication, where minimum temperature-time cycles are required to prevent junction movement.

The implanted SiO(2)-Si structures, however, can be annealed in a mildly oxidizing ambient. It is known that oxidation occurs most readily in a damaged region of a silicon single crystal, thereby removing the damage. Similarly, removal of oxide damage possibly arising from knock-on effects during implantation, will occur in the oxide film during the oxidation-anneal cycle.

It has been observed, for example, that the frequency of low-voltage capacitor breakdown events is increased after high-dosage implants (4 x 10/15/ - 10/16/ As/cm ) at 50 and 80 KeV into 400 Angstroms SiO(2)-Si structures and standard annealing in N(2), when compared with nonimplanted capacitors.

The average breakdown strength is increased and the standard deviation is decreased for similar implanted structures after annealing in 50% O(2) and 50% N(2) for 15 minutes at 900 degrees C, when compared with a 100% N anneal. Either a portion of the implant anneal time s...