METHOD OF DRY-ETCHING EVALUATION USING QUANTUM DOTS

New dry-etch processes, such as low-power reactive-ion etching (RIE) a nd electron cyclotron resonance, offer very low levels of residual lat tice damage. These levels are below the resolution limits of tradition al characterisation methods like Raman, photoluminescence, Schottky di ode, etc. We show that the single-electron charging of a quantum dot f abricated using dry etching offers a very sensitive method of damage d etection. For SiCl4/SiF4 RIE of GaAs we find a defect density of aroun d 10(15) cm(-3), which is at the level of the background impurity conc entration in the as-grown material.