Carbonaceous contamination removal for ALD, XPS and MBE systems
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EM-KLEEN and SEMI-KLEEN downstream plasma cleaner
Carbonaceous contamination and native oxide removal on samples before deposition
Surface contaminations especially carbonaceous contamination have been a headache for many thin film deposition and surface analysis systems such as ALD, epi-growth, SIMS, and XPS systems. When samples are exposed to air for 1 hour, the top surface layer of the samples will be coated with a layer of hydrocarbon contamination. Downstream plasma cleaning techniques utilize a remote plasma source attached to the load-lock chamber or the deposition/analysis chamber to generate radical species containing oxygen, hydrogen, or even fluorine to remove carbonaceous and or native oxide surface contaminations.
EM-KLEEN and SEMI-KLEEN remote plasma sources utilize electrode-less inductively coupled plasma discharge technology to avoid metal sputtering issues on other types of plasma sources. Proprietary plasma source design reduces plasma potential, which determines the energy of ions that drift out of the plasma sheath. EM-KLEEN and SEMI-KLEEN plasma sources have been demonstrated to be able to clean sample surfaces without ion sputtering damage on the top surface layer. The key to achieving ultra-clean non-damaging surface contamination removal is to build a plasma source with very low plasma potential and to select chamber materials that can resist chemical attacks from radical species generated in the plasma. SEMI-KLEEN sapphire is equipped with a sapphire plasma tube and chemical resistant vacuum seal, It can support aggressive and sometimes corrosive plasma such as NF3, CF4, H2S, HF, and NH3.
Low pressure discharge technique improves the cleaning rate for process gases such as H2 due to lower recombination loss. XPS results show that SEMI-KLEEN plasma cleaner can complete remove hdyrocarbon carbon contaminations on InGaAs samples in 2 seconds.
Reference
Rapid In-Situ Carbon and Oxygen Cleaning of In0.53Ga0.47As(001) and Si0.5Ge0.5(110) Surfaces via a H2 RF Downstream Plasma. ECS Trans. 2016 72(4): 291-302. Please download the pdf version here.