Silicon oxide formation in the disk environment

Abstract

Among many organic vapor contaminants released from structural components of hard disk drives, organic siloxanes (released from silicone gaskets, for example) are particularly ominous, as they can be released in a relatively large quantity. It is known that the presence of siloxane contaminants often leads to the formation of silicon oxide at the head-disk interface area. A plausible mechanism for the formation of silicon oxide debris in the disk environment is presented. It is envisaged that volatile siloxane oligomers such as D4 (octamethyl cyclotetrasiloxane) are released from components containing PDMS (polydimelhyl siloxane) and are repolymerized back into PDMS at the head-disk interface when catalyzed by the acidic component of a degraded lubricant. The PDMS thus formed, if heated at 300-350°C in a thin-film configuration that would permit facile infusion of oxygen, readily converts to silicon oxide with minimal depolymerizatlon.