SiGeSn Quantum Dots in HfO2 for Floating Gate Memory Capacitors

Group IV quantum dots (QDs) in HfO2 are attractive for non-volatile memories (NVMs) due to complementary metal-oxide semiconductor (CMOS) compatibility. Besides the role of charge storage centers, SiGeSn QDs have advantage a low thermal budget formation, because Sn presence decreases crystallization temperature, while Si ensures higher stability. In this paper, we prepare MOS capacitors based on 3-layer stacks gate HfO2/floating HfO2/tunnel HfO2/p-Si obtained by magnetron sputtering deposition followed rapid annealing (RTA) nanocrystallization. Crystalline structure, morphology, and composition studies cross-section transmission electron microscopy X-ray diffraction correlated with Raman spectroscopy C–V measurements carried out understanding RTA temperature effects behavior. morphology content trends explained strongly temperature-dependent segregation diffusion processes. We show that memory properties measured Al/3-layer stack/p-Si/Al controlled SiGeSn-related trapping states (deep electronic levels) low-ordering clusters at 325–450 °C, crystalline 520 530 °C RTA. Specific structures annealed is formation two kinds QDs, i.e., (2 at.%) positioned inside floating gate, high (up 12.5 located interface adjacent layers. The SiGe intermediate layer induces easier diamond structure comparison Ge-HfO2 layer. High frequency-independent windows 3–4 V stored densities 1–2 × 1013 electrons/cm2 achieved.