Magnetic Field Enhanced Plasma Assisted Atomic Layer Deposition Of AIN And Its Optical Properties

In this paper, we studied magnetic field enhanced PA-ALD of AlN films atlow temperature and its photoluminescence properties. To lower downconcentration of impurities, such as oxygen and carbon, we changeddeposition parameters and analysed the factors affected these impurities.Fourier transform infrared spectroscope (FTIR), X-ray photoelectronspectroscope (XPS) were used to analyse AlN thin films composition andconcentration of impurites. We also measured crystal characterization ofdeposited films by X-ray diffraction (XRD), optical and photoluminescenceproperties by spectroscopic ellipsometry (SE) and fluorescence spectroscopy(FS) respectively. Additionally, changes of reaction species in differentdischarge mode were carried out by optical emission spectroscopy (OES)in-situ. The conclusions are as following:(1) This work can demonstrate that it is possible to prepare crystal AlN thinfilms by PA-ALD at low deposition temperature.(2) The deposition parameters can affect concentration of impuritiesdramatically:i. The more H2concentration in N2and H2mixture gases and the longerthe mixture gases pulsed time, the lower concentration of carbon andoxygen impurities.ii. The greater magnetic field intensity, the lower concentration of carbonand oxygen impurities and the faster deposition rate.iii. It is better for preparing AlN thin films with low concentration ofimpurities at higher deposition temperature.iv. The AlN thin films deposited by microwave electron cyclotronresonance (ECR) PA-ALD technology have less concentration ofimpurities than these films deposited by radio frequency (RF) PA-ALDtechnology. v. The lower RF discharge power contributes to lower concentration ofimpurities.(3) The deposition mechanism of AlN thin films by magnetic field enhancedPA-ALD technology is that: firstly in plasma, H2and TMA molecular react witheach other, creating AlH3as reactant. And then N atoms were ionized from N2.Finally, N atoms react with AlH3to produce AlN.(4)The AlN thin films deposited by ALD have less N vacancies than the filmsdeposited by other technology.