“…They can offer some unique features such as a wide range of available work functions, high density of states around the Fermi level, and small energy perturbation due to carrier confinement, further improving memory performance. 5 Among various metal materials, ruthenium (Ru) has been studied for applications of dynamic random-access memory (DRAM), ferroelectric random-access memory (FeRAM), and complementary metal-oxide-semiconductor (CMOS) technology, [6][7][8] exhibiting good compatibility with current semiconductor technology; for example, it has high chemical and thermal stability (not easily diffused), simple dry etching capability, and good electrical conductivity even when oxidized. Furthermore, the high work function of Ru (4.71 eV) allows for creation of deeper potential wells for charge storage, which gives rise to better retention and charging characteristics.…”