0.4-μm-thick polycrystalline silicon deposited in a low-pressure CVD reactor was implanted with B to a dose of 5×1014/cm2 and then irradiated in a cw laser scanning apparatus. The laser annealing produced an increase in grain size from ∼500 Å to long narrow crystals of the order of ∼25×2 μ, as observed by TEM. Each grain was found to be defect free and extended all the way to the underlying Si3N4. Electrical measurements show 100% doping activity with a Hall mobility of about 45 cm2/V sec, which is close to single-crystal mobility at the same carrier concentration. Thermal annealing produces material with an average grain size of 1000 Å and a resistivity higher by a factor of 2.2 than that obtained with the laser anneal. Laser annealing performed after a thermal anneal reduces the resistivity to approximately the same value obtained by laser annealing only.

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The feasibility of annealing ion-implantation damage by means of a continuous high-power laser is demonstrated. An apparatus for the scanning of a semiconductor sample is described and a first-order set of optimum conditions for annealing ion-implanted Si is given. A preliminary comparison between laser and thermal annealing shows comparable results in terms of electrical activity of the annealed samples.

The use of a laser as a tool for annealing of ion-implantation damage is described. The principal results obtained are as follows: (1) electrical measurements show that activity comparable to that of a 1000 °C 30-min anneal can be obtained; (2) TEM measurements show that complete recrystallization of the damaged layer occurs during the laser anneal; (3) impurity profiles obtained from SIMS measurments show that the dopant atoms remain in the LSS profile during annealing. Simple diodes were fabricated to examine the feasibility of the method for device fabrication.