Study on Preparation and Properties of InN Films on Self-Supporting Diamond Substrates Under Different Nitrogen Flows

Abstract

Several InN film samples with superb properties were prepared on a self-supporting diamond substrate for different nitrogen flow rates using an electron cyclotron resonance plasma-enhanced metal-organic chemical vapor deposition (ECR-PEMOCVD) system. After the InN film samples were obtained, the samples were characterized via reflected high-energy electron diffraction (RHEED), X-ray diffraction (XRD), scanning electron microscopy (SEM), atomic force microscope (AFM), and electron probe micro-analysis (EPMA) to study the effect of the nitrogen flow on the quality of the InN films. The experimental results show that the variation in the nitrogen flow has a great impact on the preferential growth of the (0002) crystal plane of the InN thin film. By increasing the nitrogen flow moderately, the crystal quality of the film is improved. Under the growth condition of appropriate nitrogen flow, InN thin films with a preferred orientation along the c-axis can be obtained, and the surface of the resulting InN thin films is relatively flat. However, a high nitrogen flow does not improve the film crystal quality. The results of the experiment and of the analysis show that the InN films prepared with a nitrogen flow rate of 80 sccm have an excellent preferential orientation. The result of the EPMA test shows that the percentages of the In and N atoms in the prepared film samples are close to a ratio of 1:1, and a small amount of metal In droplets is present. In addition, the InN thin films prepared in such condition have an excellent surface morphology and composition.

Study on the Performance Impact of Introducing an InN Buffer Layer at Various Deposition Temperatures on InN Film Grown by ECR-PEMOCVD on Free-Standing Diamond Substrate

“…An InN buffer layer is the innovation of this study. In previous work, we found that the proper technological parameters for InN film growth by ECR-PEMOCVD without introducing a buffer layer were a deposition temperature of 400 • C, a nitrogen flow rate of 80 sccm, and a TMIn flow rate of 0.6 sccm [26,27]. Under these conditions, the grain size of InN was 47 nm, the surface roughness was 3.7 nm, the background electron concentration was 9.2 × 10 19 cm −3 , and the carrier mobility was 48.5 cm 2 /V•s [26,27].…”

“…In previous work, we found that the proper technological parameters for InN film growth by ECR-PEMOCVD without introducing a buffer layer were a deposition temperature of 400 • C, a nitrogen flow rate of 80 sccm, and a TMIn flow rate of 0.6 sccm [26,27]. Under these conditions, the grain size of InN was 47 nm, the surface roughness was 3.7 nm, the background electron concentration was 9.2 × 10 19 cm −3 , and the carrier mobility was 48.5 cm 2 /V•s [26,27]. When an InN buffer layer was introduced with a deposition temperature of 100 • C, the grain size of InN film was 51 nm (4 nm larger) and the surface roughness was 2.4 nm (1.3 nm less).…”

“…Higher growth pressure results in inefficient configurations of detection and analysis instruments in the growth chamber, which makes it impossible to control the size of atomic growth. However, mass production is the biggest advantage of this approach [27].…”

“…The preferential orientation, optimal surface morphology, and electrical properties of InN films can be obtained at 400 • C [26]. When the N 2 flow rate is 80 sccm, InN films have excellent preferential orientation, surface morphology, and atomic ratio [27].…”

Structures, properties and applications of two-dimensional metal nitrides: from nitride MXene to other metal nitrides

“…It is beneficial to produce nonstoichiometric MNs thin films with fewer impurities. Among various deposition methods, metal organic chemical vapor deposition is an effective method to synthesize 2D IIIANs, including AlN [185,187,193,429,430], GaN [232,233,243,245,249,251] and InN [305,308,431,432].…”