Methylamines as Nitrogen Precursors in Chemical Vapor Deposition of Gallium Nitride

Abstract

Chemical vapor deposition (CVD) is one of the most important techniques for depositing thin films of the group 13 nitrides (13-Ns), AlN, GaN, InN and their alloys, for electronic device applications. The standard CVD chemistry for 13-Ns use ammonia as the nitrogen precursor, however, this gives an inefficient CVD chemistry forcing N/13 ratios of 100/1 or more. Here we investigate the hypothesis that replacing the N-H bonds in ammonia with weaker N-C bonds in methylamines will permit better CVD chemistry, allowing lower CVD temperatures and an improved N/13 ratio. Quantum chemical computations shows that while the methylamines have a more reactive gas phase chemistry, ammonia has a more reactive surface chemistry. CVD experiments using methylamines failed to deposit a continuous film, instead micrometer sized gallium droplets were deposited. This study shows that the nitrogen surface chemistry is most likely more important to consider than the gas phase chemistry when searching for better nitrogen precursors for 13-N CVD. File list (2) download file view on ChemRxiv manuscript methylamines in GaN CVD-rev2.pdf (1.45 MiB) download file view on ChemRxiv Supporting information-rev2.pdf (1.16 MiB) Methylamines as nitrogen precursors in chemical vapor deposition of gallium nitride

The Endocyclic Carbon Substituent of Guanidinate and Amidinate Precursors Controlling Atomic Layer Deposition of InN Films

“…Chemical vapor deposition (CVD) routes to InN typically use trimethyl indium (In­(CH 3 ) 3 ) and ammonia (NH 3 ) as precursors. The low maximum temperature tolerated by the InN crystal and the poor thermal reactivity of NH 3 force InN CVD to use NH 3 /In­(CH 3 ) 3 in ratios in the order of 100,000. , Rather than relying on gas phase reactivity to form more reactive species, a surface-controlled CVD approach with time-resolved precursor delivery could be an alternative way to eliminate the high N/In precursor ratios. This approach would rely on surface chemical reactions between gas phase species and chemisorbed surface moieties.…”

Surface chemical mechanisms of trimethyl aluminum in atomic layer deposition of AlN

“…Repulsion between the surface and the methyl groups of TMA forces the nitrogen to adopt a seesaw geometry with an almost linear bend angle (165°) between the surface aluminum and TMA molecule and the bond length (2.14 Å) is slightly longer than the gas phase adduct between TMA and ammonia (2.09 Å). 32 Between the different adduct sites of the amino terminated AlN, there are first order saddle points on the PES corresponding to the transition state (TS) of TMA diffusion. When translating between two adduct sites, at the TS TMA almost returns to its planar gas phase geometry, Fig.…”

Aniline-Driven Liquid-Liquid Extraction for Methylamine-Water Separation: Process Simulation and Performance Evaluation

“…As a result, it must be eliminated or converted into biodegradable compounds before biological treatment activities may begin (Jing et al, 2015). Another chemical, methylamine (MAN -CH5N) are offshoots of ammonia with 1, 2, or all 3 hydrogen atoms substituted by methyl groups (Ronnby et al, 2019). MANs are colorless gases or compressed liquids, toxic, highly flammable, soluble in various organic solvents and have a strong fishy odor.…”