In situ Surface Passivation of Gallium Nitride for Metal-Organic Chemical Vapor Deposition of High-Permittivity Gate Dielectric

• Published in: IEEE transactions on electron devices 2011-01, Vol.58 (1), p.95-102
• Main Authors: XINKE LIU, CHIN, Hock-Chun, TAN, Leng-Seow, YEO, Yee-Chia
• Format: Article
• Language: English
• Subjects: Applied sciences; Capacitance; Chemical vapor deposition; Chemical vapor deposition (including plasma-enhanced cvd, mocvd, etc.); Cross-disciplinary physics: materials science; rheology; Density; Dielectric, amorphous and glass solid devices; Dielectrics; Electronics; Exact sciences and technology; Frequency measurement; Gallium nitride; Gallium nitride (GaN); Gallium nitrides; Gates; in situ surface passivation; interface state density; Logic gates; Materials science; Methods of deposition of films and coatings; film growth and epitaxy; Microelectronic fabrication (materials and surfaces technology); Nitrides; Passivation; Physics; Semiconductor electronics. Microelectronics. Optoelectronics. Solid state devices; Silanes; Temperature measurement
• ISSN: 0018-9383; 1557-9646
• DOI: 10.1109/TED.2010.2084410

We report the demonstration of novel techniques for surface passivation of gallium nitride (GaN), comprising the steps of in situ vacuum anneal (VA) and silane-ammonia (SiH 4 + NH 3 ) or silane (SiH 4 ) treatment for GaN, prior to the formation of high-permittivity gate dielectric in a multichamber metal-organic chemical vapor deposition tool. The effects of VA temperature and the SiH 4 + NH 3 or SiH 4 treatment temperature on interface quality was investigated. High-temperature capacitance-voltage characterization was also performed to probe the interface states near the midgap of GaN. Interface state density D it as a function of energy was extracted. Without in situ passivation, a control TaN/HfAlO/GaN capacitor has a midgap D it of ~2.0 × 10 12 cm -2 · eV -1 . This is reduced to ~4.0 × 10 11 cm -2 · eV -1 and ~2.0 × 10 10 cm -2 · eV -1 for samples that received the in situ SiH 4 + NH 3 treatment and in situ SiH 4 treatment, respectively.