Carrier transport in LPCVD grown Ge-doped β-Ga2O3/4H-SiC isotype heterojunction


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Saquib T., AKYOL F., Ozden H., Somaiah N., Sahoo J., Muralidharan R., ...More

Journal of Applied Physics, vol.135, no.6, 2024 (SCI-Expanded) identifier

  • Publication Type: Article / Article
  • Volume: 135 Issue: 6
  • Publication Date: 2024
  • Doi Number: 10.1063/5.0188055
  • Journal Name: Journal of Applied Physics
  • Journal Indexes: Science Citation Index Expanded (SCI-EXPANDED), Scopus, Academic Search Premier, Aerospace Database, Applied Science & Technology Source, Chemical Abstracts Core, Compendex, Computer & Applied Sciences, INSPEC, zbMATH
  • Yıldız Technical University Affiliated: Yes

Abstract

We report on the study of electron transport and band offset across β -Ga 2 O 3 /4H-SiC N-n isotype heterojunction. N-type β -Ga 2 O 3 of thickness 2.7 μ m was grown using low-pressure chemical vapor deposition using germanium (Ge) as the dopant on an n-type 4H-SiC substrate. The grown epilayer having ( − 201 ) orientation was verified through XRD. Temperature-dependent I-V and C-V measurements were performed (50-300 K) to investigate the transport properties across the heterojunction. First, lateral diodes were fabricated on β -Ga 2 O 3 , and from C-V, n-doping was estimated to be 2.3 × 10 17 cm − 3 in the epilayer while the Schottky barrier height was estimated to be 1.75 eV. In top-down I-V sweeps, the reverse current across the heterojunction exhibited marginal dependence on temperature, indicating a possible tunnelling-based transport mechanism, while the forward current exhibited an exponential dependence on both temperature and the applied bias. The band diagram indicated the formation of a two-dimensional electron gas (2DEG) at the hetero-interface, which was indirectly confirmed using C-V measurement and TCAD simulation at low temperatures. From the position of the Fermi level in SiC and band diagram, a conduction band offset of 0.4-0.5 eV was estimated between β -Ga 2 O 3 and 4H-SiC.