TEM STUDY OF THE 2-STEP ANNEALING OF ARSENIC-IMPLANTED (100) SILICON

Transmission electron microscopy (TEM) measurements were made to evaluate the distribution of defects remaining in arsenic-implanted silicon after annealing. Samples implanted with arsenic ions - 1 multiplied by 10**1**6 ions/cm**2 at 40 keV - were individually annealed in either one or two steps. Five samples were subjected to a one-hour preanneal - one each at 500 degree , 525 degree , 550 degree , 575 degree , and 600 degree C - in nitrogen ambient. In this temperature range epitaxial recrystallization of implantation damage can be expected. All the samples, whether preannealed or not, were then annealed for one hour at 1000 degree C in N//2, to reduce defects and to diffuse and activate the arsenic. The amount of disorder (dislocations) depended on the annealing cycle. Dislocations were minimized by preannealing for one hour at 550 degree C and then annealing for one hour at 1000 degree C. The TEM method proved much more sensitive to fine detail than channeling measurements.