Fabrication of A Sandwich Type Three Axis Capacitive MEMS Accelerometer

2013-11-06
Tez, Serdar
Akın, Tayfun
This paper presents a three axis capacitive MEMS accelerometer including individual lateral and vertical accelerometers in a same die. The three axis capacitive MEMS accelerometer is fabricated by utilizing a glass-silicon-glass multi-stack formed by a fabrication process depending on the double glass modified silicon on glass process (DGM-SOG), where the structural layer is selected to be 35 mu m thick silicon. The fabrication process uses the Au-Si eutectic bonding in the last step of the formation of the glass-silicon-glass multi-stack, eliminating the stiction risk of the suspended silicon structures to the top glass with the voltage free feature of the Au-Si eutectic bonding method, allowing to implement 2 mu m capacitive gaps for the vertical accelerometers without any pull in during fabrication, while matching 2 mu m capacitive gaps of the lateral accelerometers. The top glass wafer allows implementing not only a top electrode for the vertical accelerometer, but also a cap for the entire structure. The fabricated three axis MEMS capacitive accelerometer die is 12x7x1 mm(3). Measured capacitances of the lateral and the vertical accelerometers are 9.4 pF and 7.4 pF, but their capacitance change is similar to each other, as they are approximately measured as 90 fF/V and 100 fF/V, respectively. The Brownian noise of the lateral and vertical are estimated to be 6 mu g/root Hz and 7.6 mu g/root Hz, respectively.

Suggestions

A Bulk-Micromachined Three-Axis Capacitive MEMS Accelerometer on a Single Die
TEZ, SERDAR; Aykutlu, Ulas; Torunbalci, Mustafa Mert; Akın, Tayfun (2015-10-01)
This paper presents a high-performance three-axis capacitive microelectromechanical system (MEMS) accelerometer implemented by fabricating individual lateral and vertical differential accelerometers in the same die. The fabrication process is based on the formation of a glass-silicon-glass multi-stack. First, a 35-mu m thick < 111 > silicon structural layer of an Silicon-On-Insulator (SOI) wafer is patterned with deep reactive ion etching (DRIE) and attached on a base glass substrate with anodic bonding, wh...
Fabrication of a Three-Axis Capacitive MEMS Accelerometer on a Single Substrate
Aydemir, Akin; Akın, Tayfun (2015-11-04)
This paper presents a new fabrication approach and a design for the fabrication of a three-axis capacitive MEMS accelerometer where differential sensing is enabled for all sense directions. In this approach, individual lateral and vertical axis accelerometers are fabricated in the same die on an SOI wafer which is eutectically bonded to a glass substrate. Differential sensing for the vertical axis accelerometer is realized by defining the proof mass of the accelerometer on the structural layer of the SOI wa...
A new design and a fabrication approach to realize a high performance three axes capacitive MEMS accelerometer
Aydemir, Akin; Terzioglu, Yunus; Akın, Tayfun (2016-06-15)
This paper presents a new fabrication approach and design for a three axis capacitive MEMS accelerometer that is capable of measuring externally applied accelerations in three orthogonal axes. Individual lateral and vertical axis accelerometers are fabricated in the same die on an SOI wafer which is anodically bonded to a glass substrate. Handle layer of the SOI wafer is used as the top electrode for the vertical axis accelerometer. This accelerometer has a 2 mm(2) perforated electrode area anchored to the ...
Process Development for the Fabrication of a Three Axes Capacitive MEMS Accelerometer
Aydemir, Akin; Akın, Tayfun (2015-09-09)
This paper presents a new approach for the fabrication of a three-axis capacitive MEMS accelerometer that is capable of differentially sensing the acceleration in all three orthogonal axes. For the first time in literature, differential sensing for the out of plane direction is achieved by defining a movable sensing electrode on the structural layer of the SOI wafer that is sandwiched between two stationary electrodes defined on the glass substrate and the handle layer of the SOI wafer enabling the differen...
Noise analysis and characterization of a sigma-delta/capacitive microaccelerometer
Külah, Haluk; Yazdi, N; Najafi, K (2006-02-01)
This paper reports a high-sensitivity low-noise capacitive accelerometer system with one micro-g/root Hz resolution. The accelerometer and interface electronics together operate as a second-order electromechanical sigma-delta modulator. A detailed noise analysis of electromechanical sigma-delta capacitive accelerometers with a final goal of achieving sub-jig resolution is also presented. The analysis and test results have shown that amplifier thermal and sensor charging reference voltage noises are dominant...
Citation Formats
S. Tez and T. Akın, “Fabrication of A Sandwich Type Three Axis Capacitive MEMS Accelerometer,” 2013, Accessed: 00, 2020. [Online]. Available: https://hdl.handle.net/11511/54495.