Determination of implantation profiles by (p,y)-resonance reactions

Abstract

The importance of ion implantation in physics and technology has steadily increased over the years. It is a reliable technique to introduce species into a target, altering the chemical, metallurgical, optical and electronic properties of the target material. Measurements of the depth distribution profiles of the implanted species provide information on a wide range of topics, including ion-solid interactions, doping and diffusion phenomena. Several techniques have been developed in order to determine the depth distribution profiles of implanted ions. Destructive techniques, such as etching and sputtering provide this information, but cannot be used in diffusion studies. Rutherford backscattering on the other hand is a non-destructive method, but is not very suitable for implanted ions of which the mass is smaller than that of the target material. Nuclear reaction analysis provides a non-destructive method of determining amongst others the implantation profile of ions with a mass number smaller or similar to that of the target material into which it is implanted. Nuclear reaction analyses with narrow and strong resonances are used for high resolution measurements. Such resonances are unfortunately not available for all light elements. For this study, nuclear reaction analysis was employed to determine the profiles of 13C+ and 27 Al+ ions implanted into silicon, gallium arsenide, magnesium and stainless steel. The 13C+ ions were detected using the 13C(p,y)14 N nuclear reactions. Particularly suited for this study is the resonance at 1.75 MeV which has a resonance width of 75 eV. During the investigation of the 27 Ai+ implantation, the 27 Al(p, y)28 Si nuclear reaction was used. Here the resonance at 0.992 MeV is employed which has a resonance width of 100 eV. The projected range, straggling width, skewness and kurtosis of the implantation profiles are presented and compared to those values obtained by the theoretical predictions of the TRIM 91.14 code.