Table 4: Efficiency of metal oxide removal by exposure to a hydrogen plasma produced under conditions of electron cyclotron resonance, according to the data of ref [79] and the recent data of refs. [43, 46, 48, 80] (as indicated in the last column).

Metal Oxide Thickness δ, nm Time, h Removal Efficiency, O at/103 H at Reference
Cu Cu2O 150 0.02 ~750 [79]
Ni NiO 209 3 7.9 [79]
Fe Fe2O3 153 5 3.3 [79]
Mo MxOy ~100* 6 ~3* [79]
Ti TiO2 177 15 2.0 [79]
Be BeO ~17 1.5 ~1 [43]
Al Al2O3 ~8 ~0.5 [46]
W WO3 ~10 2.0 ~0.5 [48]
Zr ZrO2 ~14 30 ~0.15** [80]
Zr ZrO2 ~14 30 ~0.7*** [80]

*Estimated from the data presented in the paper [79]
**Ion energy 40 eV
***Ion energy 100 eV