New surface chemistries for the atomic layer deposition of oxides and nitrides

Beau Bernard Burton
Abstract & Cover

The field of atomic layer deposition (ALD) has grown substantially over the past several decades. The development of ALD as a method to deposit materials has been predominantly led by the microelectronics industry, which continues to move to submicron dimensions. This momentum towards submicron dimensions has pushed conventional thin film deposition techniques to their limits. Atomic layer deposition is a thin-film deposition technique based on sequential, self limiting surface reactions. The reactions are performed in an ABAB… binary reaction sequence to deposit a controlled and conformal film. A growing number of materials can be deposited by ALD including oxides, nitrides, sulfides, and metals. ALD has the ability to control numerous film properties such as thickness, morphology, crystallinity, conformality, and electrical properties. This thesis studied the chemistry of reactions leading to the ALD of MgO, MnO, TaN, and SiO2. Additionally, the novel chemistry for the rapid ALD of SiO2 was investigated. In situ Fourier transform infrared (FTIR) spectroscopy and quartz crystal microbalance (QCM) were conducted to monitor surface species during each half reaction and verify saturation behavior. Once the surface chemistry was understood, the films were then deposited on Si(100) substrates using the optimal deposition conditions. The films grown on Si(100) substrates were used for numerous ex situ thin film analysis techniques. X-ray reflectivity experiments were conducted to yield both film thicknesses and film density. X-ray diffraction experiments were used to determine film crystallinity. Four-point probe measurements were conducted to determine film resistivities. XPS sputter depth profiling, Rutherford backscattering measurements and in some cases SIMS measurements were also conducted to obtain the chemical composition of the films. Transmission electron microscopy and scanning tunneling microscopy were utilized to visualize the conformality of the films.

Source of Information
University of Colorado Boulder
(Boulder, USA)
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