Ultra-scaled Conformal Scavenging Electrode with Superior Tunability for Short-channel RMG FinFET Workfunction and all-ALD 3D-compatible ReRAM

摘要

A baseline TiAl-containing ALD electrode is established, with properties in line with reported workfunction (WF) materials for scaled RMG nFETs, values below 4.6eV requiring a 25Å layer. Furthermore, a novel ALD metal-compound material, MX, is shown to enable at least 10Å further scaling of the electrode stack due to its superior scavenging power. It can be finely tuned by the film thickness, allowing for a remarkable 20-30meV WF delta per ALD cycle over a minimum 600meV range. The wet etchability of the electrodes makes multi-Vt and dual-WF integration possible. MX does not degrade transfer characteristics and reliability of RMG FinFETs, while the thinner nWF electrode enables reduced gate resistance, as verified down to 20nm metal gate lengths. For the first time, taking advantage of the MX compound scavenging power to control oxygen filaments, we demonstrate an all-ALD HfO