Spectroscopic Ellipsometry for the In-situ Investigation of Atomic Layer Depositions

Project Report from the year 2014 in the subject Chemistry - Other, grade: 1.0, Dresden Technical University (Technische Universitt Dresden), course: Semiconductor Technology, language: English, abstract: Atomic Layer Deposition (ALD) is a special type of Chemical Vapor Deposition (CVD) technique based on self-terminating sequential gas reactions for a conformal and precise growth down to few nanometers range. Ideally due to the self-terminating reactions, ALD is a surface-controlled process, where process parameters other than the choice of precursors, substrates, and deposition temperature have little or no influence. In spite of the numerous applications of growth by ALD, many chemical and physical processes that control ALD growth are not yet sufficiently understood. Aim of this student research project is to develop an Aluminium Oxide (Al 2 O 3 ) ALD process from trimethylaluminum (TMA) and Ozone in comparison of two shower head designs. Then studying the detailed characteristics of Al 2 O 3 ALD process using various measurement techniques such as Spectroscopic Ellipsometry (SE), x-ray photoelec- tron spectroscopy (XPS), atomic force microscopy (AFM). The real-time ALD growth was studied by in-situ SE. In-situ SE is very promising technique that allows the time-continuous as well as time-discrete measurement of the actual growth over an ALD process time. The following ALD process parameters were varied and their inter-dependencies were studied in detail: exposure times of precursor and co-reactant as well as Argon purge times, the deposition temperature, total process pressure, flow dynamics of two different shower head designs. The effect of varying these ALD process parameters was studied by looking upon ALD cycle attributes. Various ALD cycle attributes are: TMA molecule adsorption (M ads ), Ligand removal (L rem ), growth kinetics (K O3 ) and growth per cycle (GPC).