X-ray triple-crystal diffractometer and TEM investigation of arsenic implanted silicon after pulsed laser irradiation

X-ray diffraction is widely used as a nondestructive method to investigate strains and defects in surface layers on semiconductor materials after ion implantation and pulsed laser irradiation. The advantages of triple-crystal diffractometry of (n,-n,n) arrangement (TCD) will be demonstrated in comparison with double-crystal diffractometry (DCD) and the results will be compared with TEM investigations. The specimen (111 silicon wafer) was implanted with As+ ions at 100 keV energy with various doses and annealed with 50 ns pulses from a Q-switched Nd-glass laser. TCD and DCD measurements were carried out with CuK/sub α/-radiation, 111-reflection. Depending on the implantation dose and the laser energy three different regions can be discerned by their structural properties: (1) implanted areas, (2) implanted areas with low energy annealing, and (3) implanted areas with high energy annealing. The implanted layers show enlarged lattice constants in the disturbed crystalline parts even beneath the amorphous layer at doses 1 x 1015 and 3 x 1015 As+cm-2. At a dose of 1 x 1013 As+cm-2 radiation defects are visible and at higher doses an amorphous layer occurs. After low energy annealing a strong disturbed surface layer is built up from the amorphous layer while the crystalline layer below it is not significantly changed. High energy annealed regions show recrystallization with high degree of perfection and decreased lattice constant. Only in the case of 3 x 1015 As+cm-2 residual defects in the form of point defect clusters remain. (author)