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A new record‐high room‐temperature electron Hall mobility (μRT = 194 cm2 V−1 s−1atn ≈ 8 × 1015 cm−3) for β‐Ga2O3is demonstrated in the unintentionally doped thin film grown on (010) semi‐insulating substrate via metal‐organic chemical vapor deposition (MOCVD). A peak electron mobility of ≈9500 cm2 V−1 s−1is achieved at 45 K. Further investigation on the transport properties indicates the existence of sheet charges near the epilayer/substrate interface. Si is identified as the primary contributor to the background carrier in both the epilayer and the interface, originating from both surface contamination and growth environment. The pregrowth hydrofluoric acid cleaning of the substrate leads to an obvious decrease in Si impurity both at the interface and in the epilayer. In addition, the effect of the MOCVD growth condition, particularly the chamber pressure, on the Si impurity incorporation is studied. A positive correlation between the background charge concentration and the MOCVD growth pressure is confirmed. It is noteworthy that in a β‐Ga2O3film with very low bulk charge concentration, even a reduced sheet charge density plays an important role in the charge transport properties.
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This content will become publicly available on September 8, 2026
Residual Gas Analysis for Controlling the Phosphorus Incorporation in Diamond
Various reports on phosphorus‐doped diamond growth present a prominent variation in the doping profile and the doping gradient at the substrate/epilayer interface. This warrants a closer investigation of the growth process, in particular, the gas chemistry via residual gas analysis (RGA) to determine whether a doping indicator exists that would allow a real‐time control of the phosphorus incorporation. Phosphorus‐doped diamond films are prepared by plasma‐enhanced chemical vapor deposition utilizing a 200 ppm trimethylphosphine in hydrogen gas mixture. The phosphorus‐doped diamond growth is characterized by in situ RGA, which identifies a diatomic radical (PH) formed in the hydrogen plasma. A rapid analysis response is achieved through an engineered differentially pumped component. Secondary ion mass spectroscopy (SIMS) is employed to evaluate the phosphorus incorporation in the doped diamond epilayers. The SIMS‐derived phosphorus doping profile is correlated to the RGA‐measured PH concentration. For an epilayer grown on a (111) chemical vapor deposition‐type IIa substrate with moderate miscut a significant phosphorus incorporation of 4.5 × 1019 cm−3is measured with an incorporation efficiency of about 10%. A doping model is derived that utilizes RGA for dominant growth and doping species and under consideration of various growth modes.
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- Award ID(s):
- 2003567
- PAR ID:
- 10647570
- Publisher / Repository:
- Wiley-VCH GmbH
- Date Published:
- Journal Name:
- physica status solidi (a)
- ISSN:
- 1862-6300
- Subject(s) / Keyword(s):
- diamonds, phosphorus doping, plasma-enhanced chemical vapor deposition, residual gas analyses, secondary ion mass spectroscopy
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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