Epitaxial Stress‐Free Growth of High Crystallinity Ferroelectric PbZr0.52Ti0.48O3 on GaN/AlGaN/Si(111) Substrate

다국어 초록 (Multilingual Abstract)

Due to its physical properties gallium‐nitride (GaN) is gaining a lot of attention as an emerging semiconductor material in the field of high‐power and high‐frequency electronics applications. Therefore, the improvement in the performance and/or perhaps even extension in functionality of GaN based devices would be highly desirable. The integration of ferroelectric materials such as lead–zirconate–titanate (PbZrxTi1‐xO3) with GaN has a strong potential to offer such an improvement. However, the large lattice mismatch between PZT and GaN makes the epitaxial growth of Pb(Zr1‐xTix)O3 on GaN a formidable challenge. This work discusses a novel strain relaxation mechanism observed when MgO is used as a buffer layer, with thicknesses down to a single unit cell, inducing epitaxial growth of high crystallinity Pb(Zr0.52Ti0.48)O3 (PZT) thin films. The epitaxial PZT films exhibit good ferroelectric properties, showing great promise for future GaN device applications.
A one‐monolayer MgO buffer layer enables epitaxial growth of highly crystalline, ferroelectric PbZr0.52Zr0.48O3 (PZT) on GaN/AlGaN/Si. This layer can completely overcome the lattice mismatch and is found to be not strained to the GaN allowing for the growth of epitaxial, functional PZT, paving a bright path toward oxide‐GaN electronics.