| AVS 63rd International Symposium & Exhibition | |
| Plasma Science and Technology | Thursday Sessions |
| Session PS-ThP |
| Session: | Plasma Science and Technology Division Poster Session |
| Presenter: | Mahmut Kavrik, University of California San Diego |
| Authors: | S. Wolf, University of California at San Diego M. Edmonds, University of California at San Diego X. Jiang, PIE Scientific R. Droopad, Texas State University N. Yoshida, Applied Materials L. Dong, Applied Materials R. Galatage, GLOBALFOUNDRIES S. Siddiqui, GLOBALFOUNDRIES B. Sahu, GLOBALFOUNDRIES A.C. Kummel, University of California at San Diego M. Kavrik, University of California San Diego |
| Correspondent: | Click to Email |
InGaAs and SiGe have demonstrated good potential to replace silicon in MOS devices due to their intrinsically high mobilities. In order to implement these compound semiconductors into devices, the surfaces of these materials must be atomically flat and void of surface defects, which can be accomplished by performing one of several surface cleaning techniques available: RCA standard cleaning procedure consisting of various treatments with NH4OH, H2O2, HF, HCl, and H2O to remove the native oxide and organic and ionic contaminants, UV/ozone treatments, and cleaning via thermal gas crackers and plasma sources. However, wet processing can leave organic residues and a thin layer of native oxide on the surface due to exposure to ambient conditions, while the vacuum/dry processing steps can take over 30 minutes to perform. A technique that overcomes these issues involves the use of in-situ hydrogen plasma to remove carbon and oxygen present on the surface. In this study, X-ray photoelectron spectroscopy (XPS) was employed to characterize the chemical composition of the In0.53Ga0.47As(001) and Si0.5Ge0.5(110) surfaces before and after plasma exposures. To optimize the conditions for cleaning with a plasma source, the effect of plasma power and pressure on carbon cleaning and oxygen contamination were determined. In addition, the effect of pure H2 versus an H2/Ar mixture was investigated in relation to the removal of carbon and oxygen contaminants. Using the described approach, a two second H plasma clean removed all carbon and oxygen from the In0.53Ga0.47As(001) surface while minimally etching the surface, and nearly all carbon and some oxygen were removed on the Si0.5Ge0.5(110) surface. The SiGe surface is more difficult to clean because it is more sensitive to oxygen than the InGaAs surface and can easily be explained by the high heat of formation of SiO2. In effect, the high heat of formation for SiO2 poses two challenges for cleaning of the surface: (1) trace O2 or H2O in the plasma gas are likely to form more Si-O bonds and (2) breaking Si-O bonds by atomic H will be unlikely. By incorporating the in-situ downstream plasma source and optimized experimental conditions, the efficacy of ion-less plasma treatment for the rapid cleaning of the In0.53Ga0.47As(001) and Si0.5Ge0.5(110) surfaces has been demonstrated.