研究目的
To grow highly tin-doped GaAs layers with smooth surface morphology at low temperatures using tetraethyl tin by metal organic vapor phase epitaxy, and to study the suppression of Sn segregation and droplet formation.
研究成果
Highly Sn-doped GaAs films with electron concentrations up to 2.00 × 1019 cm?3 and smooth surface morphology were achieved at 425 °C using TESn in MOVPE, suppressing Sn segregation and droplet formation. The mobility is dominated by ionized impurity scattering, and the doping profile is flat. This approach is beneficial for low-temperature growth in other materials systems, though carbon compensation is a drawback that needs addressing in future work.
研究不足
The low-temperature growth leads to higher carbon incorporation from organometallic precursors, which compensates Sn doping and may affect device performance. The study is limited to GaAs and may not be directly applicable to other materials without further optimization. The Hall effect measurements require corrections for accurate carrier concentration and mobility values.
1：Experimental Design and Method Selection:
The study used metal organic vapor phase epitaxy (MOVPE) with triethyl gallium (TEGa), arsine (AsH3), and tetraethyl tin (TESn) as precursors to grow Sn-doped GaAs films at low temperatures (425 °C and 650 °C) to investigate Sn incorporation and surface segregation.
2：Sample Selection and Data Sources:
Nominally singular (100) GaAs substrates were used. Samples were grown with varying TESn molar flow rates (
3：06 to 2 μmol/min) and fixed growth time (263 s). List of Experimental Equipment and Materials:
A horizontal MOVPE reactor, TEGa, AsH3, TESn, hydrogen carrier gas, GaAs substrates, AlGaAs and undoped GaAs buffer layers. Equipment included SEM, AFM, SIMS, and Hall effect measurement setup.
4：Experimental Procedures and Operational Workflow:
Growth was performed at
5：1 bar pressure with specific flow rates. Buffer layers were grown at 700 °C before the Sn-doped layer. Surface morphology, thickness, carrier concentration, mobility, and atomic concentrations were measured post-growth. Data Analysis Methods:
Hall effect measurements used the Van der Pauw method with corrections for degenerate semiconductors. SIMS data analyzed Sn and C concentrations. SEM and AFM provided surface roughness and morphology analysis.
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