| AVS 54th International Symposium | |
| MEMS and NEMS | Tuesday Sessions |
| Session MN-TuM |
| Session: | Integration and Packaging in MEMS/NEMS |
| Presenter: | A.V. Sumant, Argonne National Lab |
| Authors: | A.V. Sumant, Argonne National Lab O. Auciello, Argonne National Lab H.C. Yuan, Univ. of Wisconsin-Madison Z. Ma, Univ. of Wisconsin-Madison B. Kabius, Argonne National Lab V. Adiga, Univ. of Pennsylvania R.W. Carpick, Univ. of Pennsylvania D.C. Mancini, Argonne National Lab |
| Correspondent: | Click to Email |
Most devices for MEMS are currently based on silicon because of the available surface micromachining technology. The average mechanical and tribological properties of Si, however, are not suitable for many high-performance devices for current MEMS and future NEMS, such as resonators and switches which involve mechanical motion and intermittent contact. Other materials, such as SiC and AlN, have shown some promises due to better mechanical, chemical, and tribological properties compared to silicon. SiC thin films are grown at temperatures above 600°C and therefore incompatible with the CMOS thermal budget. Ultrananocrystalline diamond (UNCD), a novel material developed in thin film form at Argonne, exhibits exceptional mechanical, electrical, chemical, and tribological properties that make it excellent for high-performance MEMS/NEMS. Most importantly, UNCD is the only diamond film that can be grown at 400 °C, and retain properties comparable to that of single crystal diamond. In order to exploit excellent properties of UNCD to develop next generation of devices for MEMS and NEMS, however, such devices have to be integrated with CMOS at the wafer level, which will require a materials integration strategy and detailed understanding of degradation mechanism of CMOS upon integration. This paper discusses integration of UNCD with CMOS devices at wafer level (200 mm), which will open new avenues for building CMOS-driven devices for MEMS/NEMS based on UNCD. UNCD films were grown successfully on individual Si-based CMOS chips and on 200 mm CMOS wafers at 400 °C in a plasma-deposition system using microwave-plasma-enhanced chemical vapor deposition with Ar-rich/CH4 gas mixture. The CMOS devices were characterized before and after UNCD deposition. All devices were performing to specifications with acceptable degradation after UNCD deposition and processing. A threshold voltage degradation in the range of 0.08-0.44V and transconductance degradation in the range of 1.5-17% were observed. We also report the on cross-section TEM and RBS studies of the UNCD/CMOS interface and discuss the possible mechanisms responsible for the degradation of CMOS performance.
This work was supported by DARPA under contract MIPR06-W238 and US Department of Energy, BES-Materials Sciences, under contract DE-AC02-06CH11357.