GaAs on 200 mm Si wafers via thin temperature graded Ge buffers by molecular beam epitaxy
For heterogeneous integration of III–V compound materials on 200 mm Si wafers, we present a complete in-situ molecular beam epitaxy (MBE) process from a Ge strain compensating buffer on Si to GaAs heteroepitaxy. The whole growth process, including high-k gate oxide deposition, is performed in a 200 mm MBE cluster tool. Thin (≤0.3 μm), temperature-graded Ge buffers are investigated and the influence of the substrate temperature during Ge nucleation and anneals is studied. Using such a buffer, GaAs was grown on 200 mm Si wafers and characterized structurally and electrically using MOS capacitors.