INFLUENCE OF AMORPHIZATION ON THE DISTRUBITUON OF BORON INTRODUCED INTO SILICON.

The secondary ion - ion emission method was used in an investigation of the influence of a preliminary amorphization and subsequent annealing on the profile of boron implanted in silicon. The energy of boron ions was 100 keV. The preliminary amorphization was the result of bombardment with neon ions of 200 keV energy and 1000 mu C/cm**2 dose. Boron was implanted (500 mu C/cm**2) after a preliminary amorphization amd then silicon was annealed at temperatures below 550 degree C. The boron distribution profile was found to be narrower than in crystalline samples. When annealing was carried out at higher temperatures, the boron profile broadened considerably in the samples made amorphous by bombardment with neon ions. A significant broadening of the boron profile as a result of such annealing was not observed for crystalline samples which received similar boron doses. When the implanted boron dose was raised to 3000 mu C/cm**2, the boron profile broadened after annealing at temperatures above 600 degree C even in the samples which were not subjected to a preliminary amorphization. The observed behavior could be explained by an acceleration of the diffusion of boron as a result of formation of a large number of vacancies in the course of crystallization of an amorphous layer.