Studies of damage in low-power reactive-ion etching of III-V semiconductors

Measurements of photoluminescence intensity from GaAs and InGaAs quantum we ll heterostructures have been used as a noninvasive probe of the damage dis tribution due to very low-power dry etching. Samples were etched using SiCl 4 reactive-ion etching. Comparative studies were made on samples bombarded by the separate constituent ions of a SiCl4 discharge using a mass-resolvin g ion implanter fitted with a deceleration lens. We also examined the influ ence of more complex multicomponent discharges. We found that molecular ion s contribute less to deep damage than do atomic ions. The reason is that mo lecular ions fragment upon impact and the secondary atomic ions do not chan nel very far. Studies of laser illumination on the sample during etching sh ow that a form of radiation-enhanced diffusion can modify the damage distri bution. The net picture emerges of a complex process underlying dry-etch da mage penetration at very low energies. (C) 2001 American Institute of Physi cs.