Novel high-κ dielectrics for next-generation electronic devices screened by automated ab initio calculations

As the scale of transistors and capacitors in electronics is reduced to less than a few nanometers, leakage currents pose a serious problem to the device’s reliability. To overcome this dilemma, high-κ materials that exhibit a larger permittivity and band gap are introduced as gate dielectrics to enhance both the capacitance and block leakage simultaneously. Currently, HfO2 is widely used as a high-κ dielectric; however, a higher-κ material remains desired for further enhancement. To find new high-κ materials, we conduct a high-throughput ab initio calculation for band gap and permittivity. The accurate and efficient calculation is enabled by newly developed automation codes that fully automate a series of delicate methods in a highly optimized manner. We can, thus, calculate >1800 structures of binary and ternary oxides from the Inorganic Crystal Structure Database and obtain a total property map. We confirm that the inverse correlation relationship between the band gap and permittivity is roughly valid for most oxides. However, new candidate materials exhibit interesting properties, such as large permittivity, despite their large band gaps. Analyzing these materials, we discuss the origin of large κ values and suggest design rules to find new high-κ materials that have not yet been discovered. Automated ab initio calculations have been used to screen 1,800 oxides to find those with both a high dielectric constant (κ) and bandgap. High-κ dielectrics are needed to miniaturize microelectronic devices such as CPU, DRAM and flash memory. Ideally, they should also have a large bandgap, but no dielectric has yet been found that simultaneously has both a high κ and a large bandgap. Now, researchers in South Korea have performed first-principles calculations on almost all binary and tertiary oxides identified to date. They found that while a roughly inverse relation exists between permittivity and bandgap for most oxides, several oxides buck this trend. Based on the calculation results, they compiled a list of 13 oxides that show promise for CPU, DRAM and flash memory applications. Novel high-κ dielectric materials are identified by automated ab initio calculations on ~1800 oxides. The cubic BeO is found to possess an unprecedented material property of 10 eV for band gap and 275 for dielectric constant. Candidate high-κ oxides are suggested for microelectronic devices such as CPU, DRAM and flash memory.