Simultaneous measurement of wafer curvature and true temperature during metalorganic growth of group‐III nitrides on silicon and sapphire

We present an in situ method for the simultaneous determination of wafer curvature and true growth temperature during metalorganic vapor phase epitaxy of group‐III‐nitrides on silicon. The measurement configuration allows determining the wafer curvature by the reflections of parallel laser beams, and at the same time, the wafer temperature is measured by emissivity‐corrected pyrometry. The bending of the substrates due to strained layers and unequal thermal expansions coefficients causes a change in the surface temperature of the wafer, although the monitored process temperature is constant. Thereby both kinds of curvatures, concave and convex, lead to an opposed temperature variation. Thus, by growing LED structures on silicon a temperature shift up to 45 K with respect to the susceptor was observed. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)