Interfacial integrity enhancement of atomic layer deposited alumina on boron doped diamond by surface plasma functionalization

authors	Jaggernauth, A; Silva, RM; Neto, MA; Oliveira, FJ; Bdikin, IK; Alegre, MP; Gutierrez, M; Araujo, D; Mendes, JC; Silva, RF
nationality	International
journal	SURFACE & COATINGS TECHNOLOGY
author keywords	Nanoindentation; Boron doped diamond; Atomic layer deposition; Alumina films; Interface stability; Plasma treatment
keywords	NANOCRYSTALLINE DIAMOND; MECHANICAL-PROPERTIES; ELECTRONIC-PROPERTIES; FILMS; RAMAN; NANOINDENTATION; NUCLEATION; SILICON; POLYCRYSTALLINE; SPECTROSCOPY
abstract	High dielectric constant (high-kappa) thin films are ubiquitous in research as they impart enhanced properties to microelectronic applications. Novel combinations for coupling high-kappa and ultra-wide band gap semiconductors are being investigated for niche applications, dependent on the environmental conditions for device operation. Typically, high-kappa films such as alumina are deposited by atomic layer deposition (ALD), a technique heavily dependent on surface chemistry. This work investigates the effect of plasma surface functionalization of boron doped diamond (BDD) semiconducting films on interface quality with top-layers of ALD alumina (AlO) films, by analyzing its susceptibility to deformation; being particularly vital for electronics subjected to physically demanding environments. Alumina thin films were deposited unto as-grown (AlO-H-BDD) and O-2 plasma treated (AlO-O-BDD) polycrystalline BDD. XPS analysis performed on plasma exposed BDD films, prior to AlO deposition, demonstrated a 3% increase in O surface ligands compared to the as-grown surface. Nanoindentation analysis demonstrated plastic deformation within the alumina layer for AlO-O-BDD, for the tested loads, whereas AlO-H-BDD experienced film delamination and deformation beyond the alumina-BDD interface. TEM analysis revealed that delamination was most likely due to low cohesive strength of alumina near the interface, explained by fewer -OH and -CO (ether) BDD surface ligands on H-BDD.
publisher	ELSEVIER SCIENCE SA
issn	0257-8972
year published	2020
volume	397
digital object identifier (doi)	10.1016/j.surfcoat.2020.125991
web of science category	Materials Science, Coatings & Films; Physics, Applied
subject category	Materials Science; Physics
unique article identifier	WOS:000543496400012