THE EFFECT OF SILICON ION-BEAM MIXING ON THE BARRIER HEIGHT OF SB N-SI SCHOTTKY CONTACTS/

The barrier heights phi(B) of unimplanted and silicon ion beam mixed S b/n-Si Schottky contacts were determined by Arrhenius plots of I-V mea surements between 20 and 100-degrees-C. The dose densities phi used in this study, were 5 x 10(13); 1 x 10(14); 5 x 10(14) and 1 x 10(15) Si + cm2. At the two lower dose densities, the barrier heights of the con tact increased by up to 50%. alpha-particle channeling measurements on these contacts showed that the Si+ bombardment did cause amorphizatio n of the silicon substrate. RBS and AES depth profiles showed only sli ght diffusion or mixing of the Sb and Si. For the two higher dose dens ities, the silicon substrate was amorphized. For these samples there w as no significant increase in the barrier heights compared to the unim planted contacts. The ideality factor n of the contacts increased from 1.15 for the unimplanted contacts to 7.15 for the lowest dose contact s. For the other dose densities, the n-values decreased monotonically to a value of 3.04 at 1 X 10(15) Si+ cm-2.