A fabrication process based on structural layer formation using Au-Au thermocompression bonding for RF MEMS capacitive switches and their performance

Cetintepe, Cagri
Topalli, Ebru Sagiroglu
Demir, Şimşek
Aydın Çivi, Hatice Özlem
Akın, Tayfun
This paper presents a radio frequency micro-electro-mechanical-systems (RF MEMS) fabrication process based on a stacked structural layer and Au-Au thermocompression bonding, and reports on the performance of a sample RF MEMS switch design implemented with this process. The structural layer consists of 0.1 mu m SiO2/0.2 mu m SixNy/1 mu m Cr-Au layers with a tensile stress less than 50 MPa deposited on a silicon handle wafer. The stacked layer is bonded to a base wafer where the transmission lines and the isolation dielectric of the capacitive switch are patterned. The process flow does not include a sacrificial layer; a recess etched in the base wafer provides the air gap instead. The switches are released by thinning and complete etching of the silicon handle wafer by deep reactive ion etching (DRIE) and tetramethylammonium hydroxide (TMAH) solution, respectively. Millimeter-wave measurements of the fabricated RF MEMS switches demonstrate satisfactory up-state performance with the worst-case return and insertion losses of 13.7 and 0.38 dB, respectively; but the limited isolation at the down-state indicates a systematic problem with these first-generation devices. Optical profile inspections and retrospective electromechanical analyses not only confirm those measurement results; but also identify the problem as the curling of the MEMS bridges along their width, which can be alleviated in the later fabrication runs through proper mechanical design.


A New Temperature-Tolerant RF MEMS Switch Structure Design and Fabrication for Ka-Band Applications
Demirel, Kaan; Yazgan, Erdem; Demir, Şimşek; Akın, Tayfun (2016-02-01)
In this paper, the design and fabrication of a new radio frequency (RF) microelectromechanical system (MEMS) switch structure is presented. This RF MEMS switch is developed to get the minimum permanent deformation on the microbridge after 200 degrees C thermal treatment. The residual stress-based buckling on the MEMS bridge is simulated for 5-40-MPa/mu m stress gradient (Delta sigma) with 5-MPa/mu m steps. The temperature-dependent extension and deformation on the MEMS bridge are modeled up to 270 degrees C...
A reconfigurable RF MEMS triple stub impedance matching network
Unlu, M.; Topalli, K.; Atasoy, H.I.; Temocin, E.U.; Istanbulluoglu, I.; Bayraktar, O.; Demir, Şimşek; Civi, O.A.; Koç, Seyit Sencer; Akın, Tayfun (2006-09-12)
This paper presents a reconligurable triple stub impedance matching network using RF MEMS technology centered at 10GHz. The device is capable of covering impedances on the whole Smith Chart. The device structure consists of three variable length stubs which are designed as distributed MEMS transmission lines and two lambda(g)/8 length CPW transmission fines connecting the stubs. The variable length stubs are implemented with 12 MEMS switches over CPW lines and CPW lines connecting the switches. lambda(g)/8 ...
A parametric modeling study on distributed MEMS transmission lines
Unlu, M; Topalli, K; Demir, S; Aydın Çivi, Hatice Özlem; Koc, S; Akın, Tayfun (2004-10-14)
This paper presents a parametric study of a new model for the distributed MEMS transmission line (DMTL) structures. In this new model, the MEMS bridges which are used as the loading elements of the DMTL structures are represented as low-impedance transmission lines, rather than a lumped CLR circuit. The model also includes LC networks at the transition points from the MEMS bridges to the unloaded parts of the DMTL which are simply high-impedance transmission lines. These LC networks are employed to model th...
A low-power robust humidity sensor in a standard CMOS process
Okcan, Burak; Akın, Tayfun (2007-11-01)
This paper presents a low-cost thermal-conductivity-based humidity sensor implemented using a 0.6-mu m CMOS process, where suspended p-n junction diodes are used as the humidity-sensitive elements. The measurement method uses the difference between the thermal conductivities of air and water vapor at high temperatures by comparing the output voltages of two hea ted and thermally isolated diodes; one of which is exposed to the environment and has a humidity-dependent thermal conductance, while the other is s...
A wireless implantable multichannel digital neural recording system for a micromachined sieve electrode
Akın, Tayfun; Bradley, R.M. (Institute of Electrical and Electronics Engineers (IEEE), 1998)
This paper reports the development of an implantable, fully integrated, multichannel peripheral neural recording system, which is powered and controlled using an RF telemetry link, The system allows recording of +/-500 mu V neural signals from axons regenerated through a micromachined silicon sieve electrode, These signals are amplified using on-chip 100 Hz to 3.1 kHz bandlimited amplifiers, multiplexed, and digitized with a low-power (<2 mW), moderate speed (8 mu s/b) current-mode 8-b analog-to-digital con...
Citation Formats
C. Cetintepe, E. S. Topalli, Ş. Demir, H. Ö. Aydın Çivi, and T. Akın, “A fabrication process based on structural layer formation using Au-Au thermocompression bonding for RF MEMS capacitive switches and their performance,” INTERNATIONAL JOURNAL OF MICROWAVE AND WIRELESS TECHNOLOGIES, pp. 473–480, 2014, Accessed: 00, 2020. [Online]. Available: https://hdl.handle.net/11511/38718.