INTERFACE PROPERTIES OF OXIDIZED SILICON IN DENDRITIC WEB FORM

The praparation of silicon by the dendritic web process presents an intereating altsrnativc to the present ingot growth method since flat crystallographic surfazos can be obtained without mechanical processing. A comparative evaluation of the silicon—silicon oxide interface for web material has been carried out using the MOS capacitance method. The effect on trapped charge density of growth temperature and also of annealing the interfaces at temperatures between 680°C and 1200°C has been evaluated for both web and ingot material. The general behaviour for the dependence of trapped charge density on oxidation temperature for both web and ingot material is in good agreement with previous results for ingot material reported by Deal, Sklar, Grove and Snow (1967). However, an anomalous behaviour upon annealing has been observed for both web and ingot material which has not been previously reported. This involves a reversible increase of the trapped charge density upon annealing, with a maximum effect at an anneal temperature of approximately 800°C. A tentative model suggested for this variation in trapped charge density is based upon a physical change of structure at the silicon—silicon oxide interface causing variations in the number of dangling bonds. © 1969 Taylor & Francis Group, LLC.