Properties of high to ultrahigh Si-doped GaN grown at 550 °C by flow modulated metalorganic chemical vapor deposition

Abstract

The heterogeneous integration of III-nitride materials with other semiconductor systems for electronic devices is attractive because it combines the excellent electrical properties of the III-nitrides with other device platforms. Pursuing integration through metalorganic chemical vapor deposition (MOCVD) is desirable because of the scalability of the technique, but the high temperatures required for the MOCVD growth of III-nitrides (>1000 °C) are incompatible with direct heteroepitaxy on some semiconductor systems and fabricated wafers. Thus, the MOCVD growth temperature of III-nitride films must be lowered to combine them with other systems. In this work, 16 nm-thick Si:GaN films were grown by MOCVD at 550 °C using a flow modulation epitaxy scheme. By optimizing the disilane flow conditions, electron concentrations up to 5.9 × 1019 cm−3 were achieved, resulting in sheet resistances as low as 1070 Ω/□. Film mobilities ranged from 34 to 119 cm2 V−1 s−1. These results are promising for III-nitride integration and expand device design and process options for III-nitride-based electronic devices.

Low-field transport properties and scattering mechanisms of degenerate n-GaN by sputtering from a liquid Ga target

“…The recent focus of advanced contact processes is generally driven by CMOS-compatible, Au-free, and/or low-temperature budget ohmic contacts, [8][9][10][11][12] or n-GaN regrowth for highlyscaled AlGaN 5) or novel Al(Sc)N-based HEMTs [13][14][15] with high Al-content. The fabrication of highly n-type doped GaN films was demonstrated via Si implantation, 13,16,17) MBE, [18][19][20][21] MOCVD [22][23][24][25][26] (Si or Ge), pulsed laser deposition (PLD) 27) and reactive, pulsed sputtering (PVD) from a solid Ga target. 15,[28][29][30][31] Si implantation is used for GaN-devices but faces issues to achieve carrier densities and requires a high-temperature treatment to recover for the implantation damage.…”

“…16) MBEregrown layers are commonly applied due to the low growth temperature but face issues in terms of upscaling, throughput, and homogeneity. 20) MOCVD regrowth was demonstrated at low growth temperatures 23) with reduced growth rate, but is limited in terms of achievable n > 5 × 10 19 cm −2 at 550 °C and does not offer a non-selective growth mode 24,25) to avoid growth inhomogeneities. 25,32) Typical growth with high growth rates is conducted at higher temperatures (>950 °C).…”

“…The assumption is consistent with the increase in FWHM. Specific resistivity was derived and compared to reported data from the literature 18,19,[21][22][23][24]29,30,41,42) (Fig. 1).…”