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


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.



subject category

Materials Science; Physics


Jaggernauth, A; Silva, RM; Neto, MA; Oliveira, FJ; Bdikin, IK; Alegre, MP; Gutierrez, M; Araujo, D; Mendes, JC; Silva, RF

our authors


This work was developed within the scope of the CICECO-Aveiro Institute of Materials, projects UIDB/50011/2020-UIDP/50011/2020, and projects UIDB/50008/2020-UIDP/50008/2020, financed by national funds through the Portuguese Foundation for Science and Technology/MCTES. A. Jaggernauth kindly acknowledges financial support from the Portuguese Foundation for Science and Technology (FCT) through grant reference SFRH/BD/144984/2019. I. Bdikin wishes to acknowledge FCT for the financial support (IF/00582/2015, UID/EMS/00481/2013-FCT). Dr. Joana C. Mendes was hired by Instituto de Telecomunicacoes under the decree law Nr. 57/2016. M.P. Alegre, M. Gutierrez and D. Araujo gratefully acknowledge the research project, Proyectos Explora Ciencia, a program of the ministry of science, innovation and universities, with reference ESP2017-91820-EXP. The authors would like to acknowledge scientific contributions from Antonio Jose Silva Fernandes of I3N, Departament of Physics, University of Aveiro, and Maria Rosario Soares of CICECO, University of Aveiro.

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