Ingot and Remelt Sandblasting/Cleaning
The single-crystal GaAs ingots and polycrystalline defects must be sandblasted and cleaned to remove exterior oxides and contaminants. The sandblasting is done in a glove-box type bead blaster utilizing either silicon carbide or calcined alumina blasting media. Wet cleaning is done in wet chemical baths provided with local exhaust ventilation and utilizing HCl/HNO3 or alcohol rinses (isopropyl and/or methyl).
The following are potential hazards for ingot and remelt sandblastin/cleaning.
- Possible employee exposure to chemicals used for cleaning. Acid solutions of HCl/HNO3 and isopropyl/methyl alcohol solutions are commonly used.
- Occupational Health Guidelines for Chemical Hazards. US Department of Health and Human Services (DHHS), National Institute for Occupational Safety and Health (NIOSH) Publication No. 81-123, (1981, January). Provides a table of contents of guidelines for many hazardous chemicals. The files provide technical chemical information, including chemical and physical properties, health effects, exposure limits, and recommendations for medical monitoring, personal protective equipment (PPE), and control procedures.