In Situ X-Ray Monitoring of Metalorganic Vapor Phase Epitaxy

We demonstrate the in situ X-ray monitoring of metalorganic vapor phase epitaxy by using a four-crystal monochromator. The in situ X-ray measurement of InGaAs with a thickness of 0.3 µm on an InP substrate was achieved even under growth conditions at 620°C. Moreover, this monitoring technique is not affected by the atmosphere of the reactant source gasses. Also, the X-ray peak of the InGaAs at 300°C, is clearly separated from the InP peak in spite of the small lattice mismatch (-0.09%) without aligning the wafer. The dependence of lattice mismatch on temperature measured by this X-ray monitoring technique agrees with the dependence calculated theoretically. This technique can also be used to measure the thickness dependence of lattice mismatch and temperature dependence of in-plane compressive strain for InP on GaAs heteroepitaxy.