Effect of carbon incorporation on electrical properties of n-type GaN surfaces

Abstract

We intentionally incorporated carbon into n-GaN by high-temperature annealing of a SiN x / CN x / GaN structure to study the effect of unintentional carbon incorporation on the electrical properties of n-type GaN surfaces. X-ray photoelectron spectroscopy results showed outdiffusion of Ga atoms from the GaN surface during high-temperature annealing even when the SiN x layer was present. The current-voltage characteristics showed a drastic increase in current in the forward and reverse directions of the Schottky diode in the carbon-incorporated sample. They also showed no temperature dependence from 150 to 300 K. The current-voltage curves of the carbon-incorporated samples in the forward and reverse directions could be almost completely reproduced by assuming an exponentially decaying distribution from the surface for shallow donors.

Decomposition of trimethylgallium and adduct formation in a metalorganic vapor phase epitaxy reactor analyzed by high‐resolution gas monitoring system

“…However, to realize a high breakdown voltage performance, it is necessary to control the residual impurities in the GaN drift layer. To date, the performances of nitride‐based devices have been improved by reducing the carbon, silicon, and oxygen impurities in GaN . Reducing the carbon concentration is particularly challenging under the optimal growth conditions because carbon is a constituent element of trimethylgallium (TMG), which produces the methyl group in the reaction process.…”

Effects of Carrier Gas on Carbon Incorporation in GaN

“…[1] Carbon is a typical foreign impurity in GaN and its incorporation may influence the properties of GaN in many aspects, such as by increasing the resistivity, causing yellow or blue luminescence, [2−4] or affecting the device reliability. [5,6] It is believed that the majority of carbon contamination comes from the radicals of metal organic sources during growth, [7] which is unavoidable. However, the amount of carbon incorporation can be controlled by many growth parameters on some level such as the growth temperature, V/III ratio, growth rate and metal organic sources.…”

Effect of defects on strain state in nonpolar a-plane GaN

“…Except for sample D, biaxial strain-free lattice parameter increases with normalized intensities of YL. One possible explanation is defects such as O N or C Ga , which have long been attributed to the main origin of yellow band [25,26], act as shallow donors and can introduce additional electrons [27]; so lattice parameter increases with the increase electron concentration [28]. Detailed analysis about what specific kinds of defect result in this change in hydrostatic strain is beyond the scope of this work, but it indicates that the reduction of BSF is not necessarily along with that of other kinds of defects.…”