Structural evolution and surface reactivity in semiconductor processing

The requirements of ultra-large-scale integration have resulted in emphasizing schemes that allow the control of patterning and growth on the atomic scale. In this investigation, we explore the structural evolution and surface reactivity on the atomic scale during Column IV semiconductor processing.; Using a combined experimental and theoretical approach, we examine the fundamental interactions of low-energy ions with static and dynamic Ge(001) surfaces. Ion-induced surface point defect production was quantified experimentally in real time using in situ reflection high energy electron diffraction as a function of ion energy, ion mass, ion flux, and substrate temperature. Monte Carlo simulations of defect diffusion indicate that bulk defects may represent a significant contribution to the observed surface defect yield and that the annealing mechanism is due to recombination and annihilation of surface defects. Furthermore, Monte Carlo simulations of growth and ion bombardment demonstrate that ion-induced defects significantly affect the surface morphology during ion beam-assisted deposition.; Using x-ray reflectivity, we investigate the kinetics and structural evolution in the early stages of iron thin film growth on Si(001) substrates during chemical vapor deposition. We demonstrate that x-ray reflectivity provides a real time analysis of the surface roughness, film/substrate interface width, and film thickness on the atomic scale. We are able to separate the nucleation and growth regimes and find evidence that iron deposition on silicon proceeds three-dimensionally via an autocatalytic growth process due to a higher activation energy for thermal decomposition of the iron precursor on silicon compared to that on iron.; We also examine the surface chemistry of diethylsilane (DES) and diethylgermane (DEG) on Si(001) and Ge(001) surfaces to evaluate them as precursors for atomic layer epitaxy. We find that the adsorption of DES and DEG at room temperature is self-limiting on both Si(001) and Ge(001) surfaces. Temperature programmed desorption of the DES-saturated and DEG-saturated silicon and germanium surfaces reveal only hydrogen and ethylene evolve, depositing approximately 0.40 of a monolayer of either Si or Ge. Unfortunately, the relatively high levels of carbon contamination render the precursors unacceptable for Column IV atomic layer epitaxy.