Speakers
Description
In this work we study the oxidation surface states at SiGe/Al2O3 and Ge/Al2O3 interface using X-ray photoelectron spectroscopy. The effect of different pre-deposition chemical cleaning techniques as well as an in-situ H2 plasma treatment was investigated on the oxidation states of Ge and Si at the interface. One would expect that H2 plasma cleaning could significantly suppress the SiO and GeO oxide formation by passivating the surface. We demonstrate that depositing Al2O3 directly on top of SiGe cause the non-stoichiometric SiO and GeO formation that could be detrimental to ultimate device performance due to introducing of dangling bonds at the surface. These dangling bonds could act as trap states and reduce the mobility of the carriers in the channel. Using a germanium cap layer on top of SiGe before the Al2O3 deposition can reduce some of the non stoichiometric oxide formation. We also show that an in-situ H2 plasma cleaning of the surface prior to oxide deposition can reduce the formation of trap forming oxides significantly. Our findings can be useful for device fabrication technology based on the strained germanium on silicon material platform.
| Keyword-1 | Surface Oxidation |
|---|---|
| Keyword-2 | Plasma treatment |
| Keyword-3 | SiGe |