New Insights on Factors Limiting the Carrier Transport in Very Thin Amorphous Sn-Doped In2O3 Films with High Hall Mobility

Abstract

We demonstrated that a mass density and size effect are dominant factors to limit the transport properties of very thin amorphous Sn-doped In 2 O 3 ( a -ITO) films. a -ITO films with various thicknesses ( t ) ranging from 5 to 50 nm were deposited on non-alkali glass substrates without intentional heating of the substrates by reactive plasma deposition with direct-current arc discharge. a -ITO films with t of more than 10 nm showed a high Hall mobility ( μ H ) of more than 50 cm 2 /V s. For 5-nm-thick a -ITO films, we found that μ H was as high as more than 40 cm 2 /V s. X-ray reflectivity measurement results revealed that the mass density ( d m ) determined the carrier transport in a -ITO films. For a -ITO films with t of more than 10 nm, d m had a high value of 7.2 g/cm 3 , whereas a -ITO films with t of less than 10 nm had low d m ranging from 6.6 to 6.8 g/cm 3 . Quantitative new insight from a size effect on the carrier transport is given for a -ITO films with t of less than 10 nm. This study shows that the ratio of t to mean free path of carrier electrons governed μ H .

Tailoring of Point Defects in Polycrystalline Indium Tin Oxide Films with Postirradiation of Electronegative Oxygen Ions

“…The typical growth rate was 3.6 nm/s. The details of the RPD equipment for thin film deposition were already illustrated in ref .…”

“…This lowion-energy technology allows us to fabricate high-quality oxide films with the near-bulk densities. In fact, we have recently achieved a dense 10 nm-thick ZnO 17 and ITO 18 films having near-bulk volume densities.…”

Evolution of implicate order from amorphous to polycrystalline Sn-doped In2O3 films determined by in situ two-dimensional X-ray diffraction measurements

“…a-ITO films with a thickness of 50 nm were grown on non-alkali glass (Corning Eagle XG) substrates without intentionally heating the substrates, by reactive plasma deposition with direct-current arc discharge. [26][27][28] The source used was a sintered In 2 O 3 pellet with a SnO 2 content of 5 wt% (corresponding to 4.6 at%). The deposition conditions are described in detail elsewhere.…”

“…The deposition conditions are described in detail elsewhere. 26) The flow rate of oxygen (O 2 ) gas was 17 sccm.…”

“…The electrical resistivity ρ, carrier concentration n e , and μ H were 3.24 × 10 −4 Ω cm, 4.44 × 10 20 cm −3 , and 43.4 cm 2 V −1 s −1 , respectively. The corresponding mean free path of carriers (λ MFP ) based on the Fermi gas model 26) was 6.74 nm. The above electrical properties and λ MFP are listed in Table I.…”