摘要：The most important raw material for power device is epitaxial wafers, which is made from heavily doped polishing silicon wafers. In order to prevent dopant doped into silicon while pulling ingots spread into the epitaxial atmosphere and finally into the Epitaxial layer, while polishing wafers are produced, silicon dioxide layer will be added on the back surface of silicon wafers. There are two ways mainly used to make this silicon dioxide layer, one is named High Temperature Oxide (HTO), and the other is named Atmosphere Pressure Chemical Vapor Deposition (APCVD). The process parameter such as temperature, time and pressure are quite different from each other, also the character of the silicon dioxide layer and the effect that silicon dioxide layer have on the wafers are different from each other. In this article we will compare the difference between the two silicon dioxide layers and the ways in making silicon dioxide layers.
