Epitaxy of Tin Dioxide on Titanium Dioxide by Mist Chemical Vapor Deposition

We report on the control of carrier density in r-SnO2 thin films grown on isostructural r-TiO2 substrates by doping with Sb aiming for power-electronics applications. The carrier density was tuned within a range of 3×1016 −2×1019 cm−3. Two types of donors with different activation energies, attributed to Sb at Sn sites and oxygen vacancies, are present in the thin films. Both activation energies decrease as the concentration of Sb increases. A vertical Schottky barrier diode employing a Sb:r-SnO2/Nb:r-TiO2 exhibits a clear rectifying property with a rectification ratio of 103 at ± 1V.

mentioning

confidence: 63%

Carrier density control of Sb-doped rutile-type SnO₂ thin films and fabrication of a vertical Schottky barrier diode

Takahashi,

Takane,

Izumi

et al. 2024

“…Though it is feasible to grow the alloy films, a significant number of dislocations were observed in the films with x = 0 and 0.96, because of the large lattice mismatches with the TiO 2 substrate. 2,[24][25][26] These dislocations degrade the electrical properties of the films as they act as scattering/trap centers and leakage paths, leading to an increase in on-resistance and premature breakdown. Therefore, the dislocation density must be minimized for potential power-device applications.…”

mentioning

confidence: 99%

Rutile-type Ge_xSn_1−xO₂ alloy layers lattice-matched to TiO₂ substrates for device applications

Takane,

Oshima,

Harada

et al. 2024

We report the characterization and application of mist-CVD-grown rutile-structured Ge x Sn1−x O2 (x = ∼0.53) films lattice-matched to isostructural TiO2(001) substrates. The grown surface was flat throughout the growth owing to the lattice-matching epitaxy. Additionally, the film was single-crystalline without misoriented domains and TEM-detectable threading dislocations due to the coherent heterointerface. Using the Ge0.49Sn0.51O2 film with a carrier density of 7.8 × 1018 cm−3 and a mobility of 24 cm2V−1s−1, lateral Schottky barrier diodes were fabricated with Pt anodes and Ti/Au cathodes. The diodes exhibited rectifying properties with a rectification ratio of 8.2 × 104 at ±5 V, showing the potential of Ge x Sn1-x O2 as a practical semiconductor.

“…Therefore, r-GeO 2 , r-SnO 2 , and their alloys are routinely heteroepitaxially grown on sapphire substrates 11,17,20,[34][35][36][37][38] or r-TiO 2 substrates. [18][19][20][39][40][41][42][43] As a result of large lattice mismatches between the films and substrates, high-density crystal defects such as dislocations are introduced into the films, 11,18,34,36,39,[41][42][43] deteriorating their electrical properties (particularly, the carrier mobility). 36,41) Furthermore, such dislocations could form leakage-current paths, causing a premature breakdown of high-voltage devices.…”

mentioning

confidence: 99%

Growth dynamics of selective-area-grown rutile-type SnO₂ on TiO₂ (110) substrate

Takane

Oshima

Tanaka

et al. 2023

We demonstrated selective-area growth of r-SnO2 on a SiO2-masked r-TiO2 (110) substrate. The heteroepitaxy on a window started with Volmer-Weber mode to grow islands with {100}-, {1-10}-, and {011}-faceted sidewalls, whose growth shapes were consistent with the rutile structure’s equilibrium shape. The islands coalesced each other to make flat (110) top surface on a striped window, and lateral overgrowth started after the complete coverage of the window. Cross-sectional transmission-electron-microscopy observation of the stripe revealed that misfit dislocations propagated perpendicularly to the facet planes by the image force effect and that the dislocation density reduced substantially in the wing regions.