• Boccard, Mathieu
• Rouèche, Mélanie Nelly
• Singh, Aman Kamlesh
• Toggwyler, Nils
• Christmann, Gabriel
• Thomet, Jonathan Emanuel
• Haug, Franz-Josef
• Wyrsch, Nicolas
• Hessler-Wyser, Aïcha

Abstract

<jats:p> This paper reports on the fabrication of In[Formula: see text]Ga[Formula: see text]N (InGaN) layers with various compositions ranging from InN to GaN using a cost-effective low-temperature plasma-enhanced chemical vapor deposition (PECVD) method and analyzes the influence of deposition parameters on the resulting films. Single-phase nanocrystalline InGaN films with crystallite size up to 30 nm are produced with deposition temperatures in the range of 180–250 [Formula: see text]C using the precursors trimethylgallium, trimethylindium, hydrogen, nitrogen, and ammonia in a parallel-plate type RF-PECVD reactor. It is found that growth rate is a primary determinant of crystallinity, with rates below 6 nm/min producing the most crystalline films across a range of several compositions. Increasing In content leads to a decrease in the optical bandgap, following Vegard’s law, with bowing being more pronounced at higher growth rates. Significant free-carrier absorption is observed in In-rich films, suggesting that the highly measured optical bandgap (about 1.7 eV) is due to the Burstein–Moss shift. </jats:p>

Topics

• impedance spectroscopy
• phase
• Nitrogen
• nitride
• Hydrogen
• crystallinity
• chemical vapor deposition
• Gallium
• Indium