Real-Time Control of Lattice Matching of InGaAs on InP via Curvature-Based Operando MBE Monitoring

Real-time control of lattice matching during epitaxial growth is a longstanding challenge in the fabrication of high-performance III−V semiconductor heterostructures. Strain relaxation and lattice mismatch critically affect device efficiency, particularly in epitaxial InGaAs/InP heterostructures widely used in optoelectronics. While numerous in situ monitoring techniques have been developed for growth monitoring or atomic flux control (RHEED, quartz crystal microbalance, beam flux monitoring by the Bayard-Alpert gauge, etc), they provide only indirect and/or condition-dependent information, with a lack of the required accuracy and reproducibility, limiting their applicability for dynamic and accurate control of the growth, composition, and strain. In this work, we demonstrate a fully operando approach to composition and strain management during molecular beam epitaxy (MBE) of InGaAs on InP based on real-time magnification-inferred curvature measurements. For the first time, we use curvature evolution to dynamically adjust the temperatures of group-III elemental effusion cells in real time, with the curvature signal as the sole input. This method allows for active strain compensation, by tuning the composition, throughout the entire growth process, ensuring lattice matching under varying conditions without interrupting the growth. Our curvature-driven control strategy provides a robust, transferable solution for lattice matching control in III−V heterostructures. It paves the way for adaptive epitaxial growth protocols where composition and strain can be tuned on the fly, with implications for in situ growth process automation and advanced device fabrication.