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Plasma Sci. Technol. ›› 2018, Vol. 20 ›› Issue (6): 065508.doi: 10.1088/2058-6272/aaacc7

• Plasma Technology • Previous Articles     Next Articles

Study on deposition of Al2O3 films by plasma-assisted atomic layer with different plasma sources

 

Haiying WEI (魏海英)1,2, Hongge GUO (郭红革)2, Lijun SANG (桑利军)1, Xingcun LI (李兴存)1 and Qiang CHEN (陈强)1
  

  

  1. 1 Beijing Institute of Graphic Communication, Beijing 102600, People’s Republic of China
    2 Qi Lu University of Technology, Jinan 250353, People’s Republic of China
  • Received:2017-09-21 Published:2018-01-30
  • Supported by:

    This project was supported by National Natural Science Foundation of China (Grant Nos. 11775028, 11505013), Beijing Municipal National Science Foundation (Grant No. 4162024), KM201510015009 and the Collaborative Innovation Center of Green Printing & Publishing Technology (No. 20160113).

Abstract:

 In this paper, Al2O3 thin films are deposited on a hydrogen-terminated Si substrate by using two home-built electron cyclotron resonance (ECR) and magnetic field enhanced radio frequency plasma-assisted atomic layer deposition (PA-ALD) devices with Al(CH3)3 (trimethylaluminum, TMA) and oxygen plasma used as precursor and oxidant, respectively. The thickness, chemical composition, surface morphology and group reactions are characterized by in situ spectroscopic ellipsometer, x-ray photoelectric spectroscopy, atomic force microscopy, scanning electron microscopy, a high-resolution transmission electron microscope and in situ mass spectrometry (MS), respectively. We obtain that both ECR PA-ALD and the magnetic field enhanced PA­ALD can deposit thin films with high density, high purity, and uniformity at a high deposition rate. MS analysis reveals that the Al2O3 deposition reactions are not simple reactions between TMA and oxygen plasma to produce alumina, water and carbon dioxide. In fact, acetylene, carbon monoxide and some other by-products also appear in the exhaustion gas. In addition, the presence of bias voltage has a certain effect on the deposition rate and surface morphology of films, which may be attributed to the presence of bias voltage controlling the plasma energy and density. We conclude that both plasma sources have a different deposition mechanism, which is much more complicated than expected.

Key words: PA-ALD, mechanisms, properties