Carbon-doped GaN (GaN:C) Schottky diodes are prepared
by controlling the destruction status of the graphene interlayer (GI)
on the substrate. The GI without a sputtered AlN capping layer (CL)
was destroyed because of ammonia precursor etching behavior in a high-temperature
epitaxy. The damaged GI, like nanographite as a solid-state carbon
doping source, incorporated the epitaxial growth of the GaN layer.
The secondary ion mass spectroscopy depth profile indicated that the
carbon content in the GaN layer can be tuned further by optimizing
the sputtering temperature of AlN CL because of the better capping
ability of high crystalline quality AlN CL on GI being achieved at
higher temperature. The edge-type threading dislocation density and
carbon concentration of the GaN:C layer with an embedded 550 °C-grown
AlN CL on a GI substrate can be significantly reduced to 2.28 ×
109 cm–2 and ∼2.88 × 1018 cm–3, respectively. Thus, a Ni-based Schottky
diode with an ideality factor of 1.5 and a barrier height of 0.72
eV was realized on GaN:C. The series resistance increased from 28
kΩ at 303 K to 113 kΩ at 473 K, while the positive temperature
coefficient (PTC) of series resistance was ascribed to the carbon
doping that induced the compensation effect and lattice scattering
effect. The decrease of the donor concentration was confirmed by temperature-dependent
capacitance–voltage (C–V–T) measurement. The PTC characteristic of
GaN:C Schottky diodes created by dissociating the GI as a carbon doping
source should allow for the future use of high-voltage Schottky diodes
in parallel, especially in high-temperature environments.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.