Water vapor delivery to vacuum process for photovoltaic applications

Abstract

Oxide films are an important aspect of modern solar cells, providing passivation layers that increase cell efficiency. Uniformity of these layers is essential and affected by the distribution of gas species within the furnace. As the wafer load has gone up and wafer-to-wafer spacing has gone down, uniformity has become a concern. To address this, manufacturers are turning to sub-atmospheric furnaces. This in turn requires delivery of liquid source chemicals into sub-atmospheric pressure. This study describes tests performed on a Steamer to determine the ability of that device to deliver a set steam flow rate in a controlled manner. Multiple tests under atmospheric and vacuum pressure conditions show that the Steamer can reliably deliver steam to a sub-atmospheric process.