Dynamic control and measurement of thin film growth on a rotating wafer by reflectance analysis of inclined incident laser beam

Accurate in-situ molecular beam epitaxial growth of vertical cavity surface emitting lasers on a rotating GaAs wafer is demonstrated using inclined incident He-Ne laser reflectometry. A sinusoidal intensity variation signal is observed in the reflected light when it is monitored at a fixed position on a rotating wafer. This modulated signal is found important to give the information about the growth rate from as short as half a period of these oscillations. High precision in measurement is confirmed with reproducibility of the thickness results and its control for high accuracy is proposed. (C) 1998 Elsevier Science B.V. All rights reserved.