Electrical Effects of Three Different Encapsulants on Ion Implanted GaAs.
AIR FORCE INST OF TECH WRIGHT-PATTERSON AFB OHIO SCHOOL OF ENGINEERING
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A compararive study was done of the effectiveness of three different encapsulants for annealing ion-implanted GaAs. The three encapsulants studied were pyrolitic Si3N4 and SiO2, and plasma Si3N4. The study was limited to magnesium and sulfur implants done at room temperature with an implant energy of 120 keV. The implants were made into Cr-doped, semi-insulating substrates to doses ranging from 3 times 10 to the 12th power to 10 to the 15th power ionssq. cm. Annealing was done in a flowing H2 atmosphere at 850 C for 15 minutes. Comparisons of effectiveness were made on the basis of electrical activation efficiency and electrical profile measurements which were taken using a guarded Van der Pauw measurements system. There was not a great deal of difference in the observed electrical activation efficiencies produced by the three different encapsulants. Plasma Si3N4 caps generally produced the highest activations, but were prone to pitting during annealing. The three encapsulants produced nearly identifical electrical profiles, both for Mg and S implants. Contrary to previous studies, pyrolitic SiO2 caps produced higher activations than pyrolitic Si3N4 caps for some doses of the S implants. Author
- Solid State Physics