After the single-crystal GaAs ingot is grown within the sealed quartz ampoule, the quartz boat containing the ingot, plus the seed crystal, is removed from the ampoule, either by cutting off the sealed end of the ampoule with a wet circular saw, or heating and cracking the ampoule with a hydrogen/oxygen torch. The quartz ampoules are recycled by wet etching the condensed arsenic on the interior surface with HCl/HNO3 or H2SO4/H2O2.
The following are potential hazards for ampoule breakout.
Flammable Gases, Fire
- Possible ignition of flammable gases, resulting in fire and/or explosion. Employees may also be exposed to gases above permissible limits.
- See Possible Solutions: Flammable Gases, Fire.
- Use appropriate equipment, safety devices, and work practices associated with the hydrogen/oxygen torch.
Acid and Caustic Solutions
- Possible employee exposure to acid and caustic solutions used for etching ampoules for recycling. Solutions of HCl, H2SO4, HNO3, and H2O2 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.