Closing of micropipes in silicon carbide (SiC) using oxidized polysilicon techniques

摘要

In order to close or cover micropipes, which generally are formed in SiC bulk material, one sputters or deposits or grows a layer of silicon on the backside of a micromachined silicon carbide diaphragm. This is followed by an oxidation process. In this approach, the deposition of silicon reduces or completely plugs the micropipes. After the silicon deposition, the wafer is oxidized which completely closes the otherwise reduced micropipes. Since the oxidation process is significantly faster than silicon and SiC, it is significantly easier to close even the largest of micropipes. The thickness of the silicon, the processing for depositing or growing silicon, and the process of oxidation can be adjusted to close micropipes in different SiC materials.