An investigation on the influence of Si surface pre-treatment on the frequency dependence of the impedence of Co/n-Si Schottky barriers

The influence of Si pre-treatment on the impedance of Co/n-Si Schottky barriers is investigated. Some classical as well as some recently developed cleaning methods are applied. Only these treatments which contain a HF dip produce frequency dependence of the impedance. This frequency dependence can be removed by a sputter etch. The results allow the authors to exclude some common causes of frequency dependence previously reported. The results point to F, adsorbed at the Si surface, to be responsible for the frequency dependence. Additional experiments show that Cl produces analogous effects.