Application of high-K dielectrics in CMOS technology and emerging new technology

The maturing of high permittivity dielectric materials marks probably the most important progress in CMOS technology in the last decade. In this paper we review three critical applications of high-K dielectrics that not only allow continued scaling of CMOS logic and memory devices, but also open up new technology opportunities for more powerful System-on-Chip (SoC) devices. High-K gate dielectric will be able to reduce gate leakage for sub-90nm devices to an acceptable level and thus will find great use in portable devices. Ilowever, many technical issues still need to be addressed, such as fixed charges, interface traps that reduce carrier mobility and boron penetration. Maintaining DRAM capacitor at a fixed value of ∼ 30 fF per cell is also becoming increasingly unachievable at each technology node. New high-k dielectrics with very high permittivity such as SBT are being investigated for DRAM application, but key materials development for insulating the high-k from other processing hazards such as hydrogen and plasma damage remains major challenges. High-k ferroelectrics have achieved success in FeRAM recently. The development of conducting oxide electrode such as IrO 2 has greatly improved the endurance of ferroelectric memories from 10 7 to > 1012 cycles. However, the requirement for high temperature processing of ferroelectric materials continue to hamper efforts to integrate FeRAM into SoC devices and recent progress in low-temperature ferroelectrics holds promise to large scale applications. Overall, high-k dielectrics hold keys to many future IC applications and there are many opportunities in meeting these challenges.