Zinc Oxide Grown by Atomic Layer Deposition

Abstract

Given the increasing importance of atomic layer deposition (ALD) in present semiconductor industry, the basic objective of this chapter is to highlight the versatility of zinc oxide grown by this method. Depending on growth conditions, ALD is able to provide epitaxial or polycrystalline ZnO films with various orientations and diverse surface morphology. Likewise, electron concentration, and thus conductivity, can be tuned in a wide range reaching a low resistivity of ~10−3 Ω cm, which can be further decreased by Al doping to ~10−4 Ω cm. On the other hand, highly resistive samples obtained under oxygen-rich conditions provide a good starting point for acceptor doping. Moreover, typical advantages of the ALD method, such as conformal coverage of surfaces with highly developed morphology, possibility of low temperature growth, and thickness control in nanometer scale, make ZnO–ALD an interesting material for various applications. Some of them such as Schottky junction, 3D memory, UV sensor, and surface enhanced Raman spectroscopy platforms will be discussed here.