Study On Preparation And Properties Of ZnO Film By Atomic Layer Deposition Technique

As the one of the third generation of semiconductor materials, ZnO with direct wind band gap can be widely used in manufacturing the blue green and uv optoelectronic devices. And it also has a high saturated electron drift velocity, low dielectric constant, etc. So, ZnO has become the research focus in the semiconductor materials. Atomic layer deposition (ALD) is a film preparation techniques developed in recent years. Because the films deposited by ALD technique have a lot of advantages, the atomic layer deposition (ALD) has attracted much attention of people. In this paper, we would use atomic layer deposition apparatus that we developed and manufactured to deposite new semiconductor materials of ZnO on the sapphire substrate. We also test and analyze crystal structure and morphology of ZnO.First, the effects of DEZn times on the properties of ZnO thin film deposited by Thermal ALD technology were investigated. The result indicate that the thickness and the grow rate of the ZnO film has weak relationship with the time of the pre-cursor(DEZN). But with the increase of the time, the crystallization performance and roughness of film has been improved, and the conductivity of film also become enhanced.Second, We studied that growth cycles affected the properties of ZnO thin film deposited by Thermal ALD technology. The experimental results show that, As the growth cycles increasing, the films grain size increases obviously and crystalline have been improved. When the growth cycle is1000cycles, grain size can be up to50nanometers, that is about2.5times of200cycles. So we can adjust the grain size of ZnO thin films by controlling growth cycles.Third, For technical difficulties and the problems of conventional ALD, Variable Electric Field-assisted Atomic Layer Deposition (E-PEALD) technology is put forward for the first time. And we analyze the action mode of E-PEALD technology of reactants.Fourth, We also studied that electric field direction affected the properties of ZnO thin film deposited by E-PEALD technology. It was found that we can adjust electric field crystallographic orientation of ZnO thin films by controlling electric field direction. In addition, the effects of electric field intensity on the properties of ZnO thin film deposited by E-PEALD technology were investigated. In the direction of the electric field (Zn-/O+), we can improve the films (002) orientation of single crystal by increasing electric field intensity.