Recent advances in the MOVPE growth of indium nitride

Abstract

Since a few years, indium nitride promising properties for device applications have attracted much attention worldwide. Huge efforts are dedicated to optimize indium nitride growth. However, this growth is extremely challenging, in particular using the metal organic vapor phase epitaxy (MOVPE) technique which exhibits very low growth rates. This may explain why most of the samples available in the scientific community, which also present the best electrical properties, were grown by molecular beam epitaxy (MBE). However, up to date, no intrinsic indium nitride layer was obtained. InN epilayer crystalline quality suffers from the lack of lattice matched substrates, leading to the use of double‐step growth process. In this paper, we show that InN low lateral growth rate is a limiting parameter for efficient double‐step growth process. But, we also report that the use of CBrCl3 during InN growth enhances the lateral growth rate. To improve the growth rate along the c‐axis, we investigate alternative precursors for both nitrogen and indium species. We show that ammonia remains the best precursor, but combined with triethylindium, the growth rate increases with optimum crystalline quality. Finally, we compare MOVPE‐grown and MBE‐grown InN layers in order to understand the difference observed on the electrical properties. We show how thermal annealing can improve the MOVPE‐grown InN layers leading to similar electrical properties than reported in MBE‐grown samples. The role of ammonia as source of hydrogen is also discussed.

Dependence of InN properties on MOCVD growth parameters

“…Increasing growth temperature from 500 °C to 565 °C results in decreasing ntype background carrier concentration from 1.33x10 19 cm -3 to 4.1 x10 18 cm -3 (Table 1). The origin of high background carrier concentration is usually explained by H and O impurities which are the main reasons [6], but we also have indication about decreasing N vacancies in the interface region measured by positron annihilation spectroscopy (PAS); therefore sheet carrier concentration is decreasing [7]. As a result of carrier concentration decrement, the Hall mobility is increasing from 536 cm 2 /Vs to 1200 cm 2 /Vs.…”

Thermal study of an indium trisguanidinate as a possible indium nitride precursor

“…The InN film decomposes to indium metal and N2 gas even at deposition temperatures as low as 500 °C, 4 setting an upper limit for the deposition; this forces the use of use NH3/In(CH3)3 ratios on the order of 100,000 due to the poor reactivity of ammonia at these low temperatures. 5 An alternative approach for depositing InN is a time-resolved CVD technique where the poor reactivity of NH3 is overcome by allowing it to react with chemisorbed indium-containing surface moieties rather than relying on this reactivity in the (dilute) gas phase. Recent studies of InN deposition by atomic layer deposition (ALD) have shown that it is indeed possible to deposit InN with high crystalline quality using In(CH3)3 and nitrogen plasmas.…”

Non-parabolicity and inter-valley transitions within zinc-blende indium nitride

“…Indium nitride (InN) is a narrow-gap III-V nitride semiconductor that has been a focus of interest within the electronic materials community for more than a decade now [1]. This interest has been fueled, in large measure, by its considerable potential for device applications [2,3].…”