Low-temperature pre-treatments in a vertical epitaxial reactor with an improved vacuum load-lock chamber

Low-temperature (< 750 degrees C) surface preparation for epitaxial growth poses extra challenges for both hardware of a vertical batch epitaxial reactor and chemistry of in situ pre-epi treatments. The vacuum load-lock chamber of the vertical batch tool has been improved to ensure that residual moisture and oxygen concentrations are suppressed to less than 0.1 ppm. Si- based and Cl-based gases or a mixture of these gases are investigated in terms of effectiveness to remove interfacial residual oxygen at low temperatures (< 750 degrees C). Under an optimized process condition, we found that interfacial oxygen can be reduced to less than 1 x 10(12) cm(-2) levels by low-temperature treatment with a mixture of Si- based and Cl-based gases.