# Paper review: A Thin-Film Piezoelectric-on-Silicon MEMS Oscillator for Mass Sensing Applications ###### tags: `ECE697SD` `paper review` ## Abstract They uses lead zirconate titanate(PZT) thin-film piezoelectric layer deposited on a single-crystal silicon substrate to realize a length-extensional mode resonator. This resonant has a frequency of 5.12MHz and a quality factory(Q) of 311. The concept of MEMs resonant includes a mechanically resonating micro-structure, which is electrically brought into resonance. MEMS resonator is suitable for low-cost batch fabrication compaired to a quartz resonators. The MEMS resonators have higher potential levels of integration with microelectronics and circuits at the die or package level. That's because of traditional quartz resonators cannot be integrated with the CMOS and microelectronics circuit on a chip. They Categorize mechanisms that are generally utilized to drive and sense the silicon resonators. 1. electrostatics 2. piezoresistivity 3. piezoelectricity ### Piezoelectric resonators it has a high electrmechanical coupling coefficient. :::success 1. Can provide a high quality factor(Q) value, especially in high frequency 2. Owing to the DC bias voltage is not being necessary for driving it 3. It could simplify the measurement setup 4. Make the integrated application more convenient and less demanding ::: :::danger lowest motional resistance among others ::: #### Operations of piezoelectric resonators 1. usage of piezoelectric materials to directly convert electric polarization to mechanical stree, and vice versa. Thin-film piezoelectric-on-silicon (TPoS) MEMS resonators use its layer to drive or sense the acoustic waves in a substrate material such as silicon. [18-21] It provide higher resolution and mass sensitiveity. Thus, one of the application utilities for mass sensors and particulate matter(PM 2.5) sensors. This proposal can also benefits the sensor with small size, easy to integrate, and real-time detection. --- # Paper review: MEMS Resonators for Frequency Reference and Timing Applications ###### tags: `ECE697SD` `paper review` ## Abstract: The state-of-the-art technologies are focusing on improving the overall performance of MEMS resonators. For exmaple, quality factor(Q), motional impedance, temperature sensitivity, and initial frequency uniformity. These will be reviewed in detailed. They also listed challenges for commercialization of MEMS resonators, and future works and development trends. They intends to provide an overlook and overview for possible research directions in frequency reference and timing applications. With outstanding reliability, unique multi-frequency functionality on a single chip, and high accuracy, MEMS resonators show its potential for replacing the quartz crystal resonators. ## Introduction Resonators are the most essential components for building reference oscillators. Mechanical and electrical oscillators are two main families for oscillators. Mechanical oscillators can also be divided into two group: Quartz crystal and MEMS oscillators. MEMS oscillators have experienced rapid growth, shown its electrical performance with well-established :::info Market of MEMS based oscillator is valued from USD 99 million in2018 to USD 604 million by 2024, with a compound annual growth rate of 38%. ::: Due to MEMS oscillators' compact size, best reliability, high temperature stability, and good compatibility with CMOS, it demonstrates its potential to replace quartz crystal resonators. :::warning Still, quartz crystal resonators are still dominating the timing market. However, they are suffered from several disadvantages. ::: ![](https://hackmd.io/_uploads/SJI6WFnmj.png) ### MEMS :::success 1. fabrication process, MEMS resonators are batch fabricated on wafer using semiconductor processes 2. it is more immune to external environmental noises, e.g., vibrations, shocks, and electromagnetic interferences(EMI) 3. Multi-frequency ersonators can be integrated on a single chip for MEMS resonator. ::: :::danger [1. iphones are allergic to helium](https://zh.ifixit.com/News/11986/iphones-are-allergic-to-helium) [2. MRI disables every IOS devices in facility](https://www.reddit.com/r/sysadmin/comments/9mk2o7/mri_disabled_every_ios_device_in_facility/) ::: ### Quartz :::success the resonant frequency ::: :::danger 1. Quartz resonators are individually cut using precision manufacturing technologies. ::: # Paper Review: Commercial Crystal and MEMS Oscillators Characterized at Deep-Cryogenic Temperatures ###### tags: `ECE697SD` `paper review` ## Abstract: They focus on cryogenic frequency generation with commercially available oscillators. They tested eight commercial crystal and MEMS oscillators, generating 50 or 100 MHz signals, were tested over a wide temperature range from 300K(26C room temperature) down to 4 K(-269C). Comparing to majority of crystal oscillators can perform fully functial even at extremly low temperatures, the MEMSs show apparent ageing effects after cooling cycles. However, despite the crystal-based devices decreased by 0.1%, its power consumption and signal amplitude perform slightly higher at cryogenic temperatures. ## Intoduction: The interface between quantum-classical will produce heat due to the wiring, and it become one challenge to the quantum computers. Typically, quantum computers operates below 100mK, and it still require many classical electronics for read-out and control. To overcome this temperature issue, another approach is placing the control interface close to the quantum processor at cryogenic temperatures. Recently, many works shows that CMOS can benefits from altered device parameters, but it suffers from an increased threshold voltage at cryogenic temperature.