Electric-field-enhanced emission and annealing behaviour of electron trapsintroduced in n-Si by low-energy He ion bombardment

The isochronal annealing and electric-field-enhanced emission properties of three defects (EHe203, EHe584 and EHe211), observed in low-energy He-ion b ombarded n-Si, were studied using deep level transient spectroscopy. EHe203 (E-C - 0.20 eV) and EHe584 (E-C - 0.58 eV) were thermally stable up to sim ilar to 400 degrees C after which their removal was accompanied by the intr oduction of a secondary defect EHe211 (E-C - 0.21 eV). EHe211 was thermally stable at 650 degrees C, The emission rate of EHe203 was significant for e lectric fields above 4 x 10(4) V cm(-1), and was enhanced by over 3 carders of magnitude for a corresponding three-fold increase in electric field. Th e emission rate of EHe211 was only weakly field dependent over the electric field range studied, while that of EHe584 remained constant for electric f ields between 3 x 10(4) and 9 x 10(4) V cm(-1). EHe584 has been proposed to be an acceptor-type defect. It was found that square wells of radii 57 Ang strom and 40 Angstrom described the potentials induced by EHe203 and EHe211 , respectively, reasonably well. Alternatively, Gaussian potential wells wi th alpha = 20 Angstrom and V-0 = 0.30 eV (EHe203) and alpha = 12 Angstrom a nd V-0 = 0.35 eV (EHe211) could be used to fit our experimental data.