| Popis: |
The effects of the initial surface conditions, the bombardment temperature and the post-bombardment annealing temperature on the residual damage in Si(OO1) due to 110 eV Cl+ and Ar+ irradiation were studied. It was found that the damage produced in HF-etched samples with contaminated surfaces (carbon and oxygen impurities) was greater and more stable than that for either atomically clean or native oxide covered surfaces. ‘The damage following high-temperature bombardment (1073 K) was closer to the surface and more stable than that for RT bombardment. It is shown that a significant amount of the damage created in silicon by 110 eV Cl’ and Ar+ bombardment at RT remains after annealing to temperatures as high as 1073 K. 1. ln~tion Low-energy ion bomb~dment has become an important technique for etching semiconductor materials for device applications [l], and for the preparation of the atomically clean surfaces which are essential for the effective growth of epitaxial layers and fundamental surface science studies. As device dimensions are reduced, the need to develop low-temperature process for cleaning substrates, growing and doping films and dopant activation becomes more important. However, embedment of se~~nductor materials with ions, even in the low-energy region close to penetration and displacement thresholds (few 10 eV) introduces defects in the form of atoms displaced from their lattice sites via collisions and/or due to the incorporation of atoms of the bombarding species. In addition, the high mobility of interstitial atoms at low temperature in materials such as silicon and diffusion of the bombardment species can increase the depth of the damaged region to significantly beyond the total energetic range of the incident particles [Z]. These effects present one of the fun~ental limitations in the application of low-temperature, ion-assisted processing to the fabrication of nanometre electronic device structures [3]. |
