Development of a target holder assembly for studies of Ion beam irradiation effects in solids maintained at LN_2 temperature

摘要

Constant cooling of the substrate or the targets during the thin films deposition or ion beam irradiation is often required for the studies of structural and associated electrical, optical and mechanical properties of materials. It is well known that substrate temperature plays important role in dictating the structures of ultra-thin films, which in turn governs the performance of the novel devices based on the physical properties associated with the thin film systems. In case of ion beam irradiation or ion implantation, the modification such as new phase or structures formation in the implanted zones is closely related to target temperature and hence the physical properties. Several methods have been developed for the characterization of surface properties at very high or very low temperatures. As high or ultra high vacuum is necessary for caring out such important investigation so proper target holder fabrication which can be kept at variable temperature starting from liquid helium to as high as 850°C. As liquid helium temperature is not always required and liquid nitrogen is easily available so we have fabricated a target holder, which can be maintained at low temperature in high vacuum. The present paper describes a simple experimental set-up where the target can be maintained at liquid nitrogen (temp. -175°C) during thin film deposition by magnetron sputtering or during ion beam irradiation.