High electron mobility AlGaN/GaN heterostructure on (111) Si

Abstract

Room-temperature Hall mobilities exceeding 900 cm2/V s are obtained for AlGaN/GaN heterostructures on (111) Si by single-temperature flow modulation organometallic vapor phase epitaxy. Thin pseudomorphic AlGaN top layers exhibit a 1.5 nm surface roughness and induces a two-dimensional electron gas sheet carrier concentration of 1.0×1013 cm−2. The GaN buffer layer has a background carrier concentration of 1.0×1015 cm−3, 130 arcsec x-ray diffraction full width at half maximum, and a low-temperature photoluminescence linewidth of 10 meV. An AlN nucleation layer provides static electrical isolation between the AlGaN/GaN and the conducting Si substrate. Large crack-free areas of high-crystalline-quality epitaxial material are obtained and have been successfully used for transistor fabrication.

AlGaN/GaN HFETs on Fe‐doped GaN substrates

“…The Fe concentration slopes (2) are almost the same in all the samples despite the difference in growth/annealing time. This suggests that Fe incorporation in GaN proceeds via surface segregation from the interface to around 1 μm.…”

“…3. Fe profile in the nominally undoped epilayer GaN is composed of three parts with different slopes ((1), (2), and (3)) as shown in Fig. 3.…”

“…Many groups have reported AlGaN/GaN HFETs on various substrates, for example, sapphire, Si, SiC, and GaN [1][2][3]. It is well known that GaN epilayers grown on sapphire, Si, and SiC have high density defects due to the differences in lattice constant and thermal expansion coefficient between GaN and these substrates.…”

Integrated GaN photonic circuits on silicon (100) for second harmonic generation

“…GaN exhibits strong second-order nonlinearity [11][12][13][14], with a χ (2) coefficient of the same order as LiNbO 3 . Its outstanding electrical, thermal and optoelectronic properties have enabled a broad range of technological applications including high speed and high power electronics [15], blue/UV light emitting and laser diodes [16]. Furthermore, GaN has an extremely wide transparency window spanning UV, visible and far infrared wavelengths.…”

Cathodoluminescence study of micro-crack-induced stress relief for AlN films on Si(111)

“…8,9 In this study, we have performed a detailed spatially and spectrally resolved cathodoluminescence (CL) study for high-quality thin AlN films grown on Si(111), which could serve as a practical and convenient substrate for future synthesis and processing of AlGaN-based devices. 10,11 Because of the large bandgap of ;6 eV for AlN, the high-energy and sharply focused electron beam (e-beam) employed in CL serves as an excellent probe for locally generating excess electrons and holes and subsequently measuring variations in the luminescence efficiency caused by microcracks, dislocations, and impurities. 12 While the presence of thermal stress-induced microcracks is clearly undesirable when attempting to obtain high-quality thin film growth of III-nitride films on Si, the presence of cracking enables a study of the stress-induced energy shifts in the optical transitions that can be measured with a high-resolution spatially resolved probe, such as with CL.…”