Influence of Wet and Dry Ambients on Fast Surface States of Germanium

Abstract

Simultaneous measurements of surface recombination velocity and added trapped charge density in the fast states as a function of surface potential were carried out on an w-type specimen which was subjected to the following gaseous ambient cycles: (a) room air-vacuum, (b) dry air-vacuum, (c) dry oxygen-vacuum, (d) dry nitrogen-vacuum, (e) wet nitrogen-vacuum, and (f) wet oxygen-vacuum. The most important results of these measurements were: (1) Dry nitrogen had no influence whatsoever on any of the surface-state parameters, (2) dry oxygen affected only the density of states and the unperturbed surface potential, and (3) wet nitrogen and wet oxygen had almost the same and most pronounced effect on the fast surface states.

The Stabilization of Germanium Surfaces by Ethylation

“…The discrepancy between the photovoltage and the field effect measurements for the case of the wet ambients is probably due to irreversible changes caused by the action of the high electric fields on the surface in the presence of the wet ambient, on the surface. Such effects on etched surfaces have also been reported by other investigations (20)(21)(22) and might be due to ionic movement in a water film on the surface.…”

Eigenschaften gewöhnlicher Halbleiteroberflächen

“…Bei den mit den iiblichen Atzmitteln behandelten O F ist im wesentlichen nur der bei F, = 3-. - [129] bringt eine (1 11)-OF direkt nach dem Atzen in ein Vakuum von 10-4 mm Hg. Nach zwei Tagen stellt er ebenfalls eine Abnahme der Anzahl der Rekombinationsterme fest (Tabelle 1 in 11291).…”

“…Nach weiteren 15 Tagen in diesem Vakuum zeigt sich jedoch eine Zunahme der Termzahl. Bei beiden Autoren geht mit der Anderung von N , eine [129]. DORDA [137] findet eine reversible Anderung der Termdaten in Abhangigkeit von der relativen Feuchte.…”

Surface Recombination Measurements on Clean Germanium Surfaces

“…This progressive increase was also observed by Madden and others, 2 and is due to the removal of water vapor from the sample. 3 The recombination velocity for the clean surface varied between 730 cm/sec and 480 cm/sec, Madden 2 quotes a value of 460 cm/sec and J. T.…”