| AVS 62nd International Symposium & Exhibition | |
| Electronic Materials and Processing | Monday Sessions |
| Session EM+NS+PS-MoA |
| Session: | More Moore! II |
| Presenter: | Kai-Ting Hu, UC San Diego |
| Authors: | K. Sardashti, UC San Diego K. Hu, UC San Diego S. Madisetti, College of Nanoscale Science and Engineering, Albany-SUNY K. Tang, Stanford University S. Oktyabrsky, College of Nanoscale Science and Engineering, Albany-SUNY P.C. McIntyre, Stanford University S. Siddiqui, Globalfoundries B. Sahu, Globalfoundries N. Yoshida, Applied Materials Inc. J. Kachian, Applied Materials Inc. A.C. Kummel, UC San Diego |
| Correspondent: | Click to Email |
Silicon-Germanium has shown a great promise for future CMOS technology by combining the high hole and electron mobility of Ge with the ability to have both tensile and compressive strain by fabrication of alloys of higher and lower Ge content. In contrast to Si, SiGe native oxide is a combination of SiO2 and GeO2, SiGeOx, which has low interface quality and stability in comparison with SiO2 due to the presence of the GeOx. Therefore, instead of thermal oxide growth, it is necessary to employ atomic layer deposition (ALD) for gate oxide deposition in SiGe MOS devices. The effects of the ex-situ wet chemical clean (such as HF and (NH4)2S dip) and in-situ NH3 plasma clean prior to ALD, were determined on Al2O3/SiGe; interface quality quantified by oxide leakage, interfacial trap density, and near-interface trap density. MOS capacitors fabricated by Al2O3 ALD at 120°C. Compared to HF clean, both ex-situ (NH4)2S clean and in-situ NH3 plasma resulted in smaller density of interface and smaller leakage current in accumulation. Furthermore, both methods resulted in high surface stability in air; queue times up to an hour could be tolerated. Angle-resolved X-ray photoelectron spectroscopy (AR-XPS) measurements on SiGe(001) with 0.8nm thick Al2O3 showed that (NH4)2S clean significantly reduces the amount of GeOx at the in Al2O3/SiGe(001) interface, compared to HF clean.