Theoretical and Empirical Insight into Dopant, Mobility and Defect States in W Doped Amorphous In₂ O₃ for High-Performance Enhancement Mode BEOL Transistors

Atomic Layer Deposition of WO3-Doped In2O3 for Reliable and Scalable BEOL-Compatible Transistors

“…This aspect distinguishes ALD from sputtering of the metal oxide films, which involves a line-of-sight for energetic species from the target to the substrate that can induce defect formation during growth. Compared with other oxide semiconductor materials deposited by different methods, − the ALD IWO FET with 2 atom % W demonstrates superior stability under both PBS and NBS, as shown in Figure .…”

“…However, high dopant concentrations of zinc oxide and gallium oxide can suppress the carrier mobility due to the decreased In 2 O 3 fraction in the films. Recent research has explored doping In 2 O 3 films with only several atom % tungsten in the form of tungsten oxides (WO 3 ) to form “IWO” as an alternative semiconducting oxide. , Prior literature suggested that this approach might leverage tungsten’s higher oxygen-bond dissociation energy to enhance threshold voltage stability without significant mobility loss . Reported IWO FETs have demonstrated exceptional on/off ratios, ultrathin channels, and highly scaled gate lengths.…”

“…15,16 Prior literature suggested that this approach might leverage tungsten's higher oxygen-bond dissociation energy to enhance threshold voltage stability without significant mobility loss. 17 Despite such advancements, the method for depositing the IWO films reported to date is limited to sputtering, a physical deposition technique that involves using energetic species in a plasma struck near a source target or targets to deposit films at relatively low chamber pressures. This method, however, faces limitations in growing conformal films on surfaces with complex topographies, a critical requirement for channel materials in advanced gate-all-around or FinFET structures.…”