MEMS and Microsensors

Professor: Giacomo Langfelder
Teaching Assistants: Giorgio Mussi, Marco Bestetti

The aim of the course is to introduce the basic concepts of some types of electronic devices which allow to acquire physical chemical and biological information from the outside world and also to act on it on it at microscopic level. The attention is focused on the operating principles of optical image sensors and of Micro-Electro-Mechanical-Systems (MEMS). Their integration in more complex systems is also considered. The performances of these devices are discussed with particular reference to their biomedical applications. Class-works about specific case-studies as well as experimental laboratory activity are foreseen.

News and Communications
Welcome folks, in this page you will find the slides and the detailed and discussed solutions of numerical exercise!

The slides are updated the day (or a few days) before the lecture (with the last-year version already available). The numerical exercises solutions are uploaded after the corresponding lecture.

The most updated course schedule is always available here!

Helpful slides, reviewing basics of electronics for non-electronic students, and focusing on the purpose of the course, have been added! Check further below on this page!

During the classes I will sometimes show results of some Finite Element Method (FEM) simulations. The corresponding videos are available 
here (now available also as GIF images).

Slides of the course
C01 Course Introduction

C02 MEMS Technology
C03 MEMS Spring Mass Damper
C04 MEMS Accelerometer Part 1
C05 MEMS Accelerometer Part 2
C06 MEMS Accelerometer Part 3
C07 MEMS Accelerometer Part 4
C08 MEMS Resonator Part 1
C09 MEMS Resonator Part 2
C10 MEMS Resonator Part 3
C11 MEMS Gyroscope Part 1
C12 MEMS Gyroscope Part 2
C13 MEMS Gyroscope Part 3
C14 MEMS Gyroscope Part 4
C15 MEMS Gyroscope Part 5
C16 MEMS Gyroscope Part 6
C17 MEMS Magnetometer Part 1 - old version
C18 MEMS Magnetometer Part 2 - old version
C19 MEMS Magnetometer Part 3 - old version
C20 MEMS Characterization Part 1 - old version
C21 MEMS Characterization Part 2 - old version

C22 CMOS Sensors Basics Part 1 - old version
C23 CMOS Sensors Basics Part 2 - old version
C24 CMOS APS3T Part 1 - old version
C25 CMOS APS3T Part 2 - old version
C26 CMOS APS3T Part 3 - old version
C27 CMOS APS4T Part 1 - old version
C28 CMOS APS4T Part 2 - old version

E01 Accelerometer Design
E02 Accelerometer Readout
E03 Torsional Accelerometer
E04 CAD Perfofated Capacitor
E05 Resonator Design
E06 Oscillator Design
E07 Gyroscope Mechanical Design
E08 Gyroscope Drive Design
E09 Gyroscope Sense Design
E10 Magnetometer design
E11 Magnetometer readout
E12 Microphone design
E13 CAD MEMS accelerometer
E14 CAD gyroscope redesign

E15 Photocurrent
E17 CAD pixel
E18 DR
E19 PTC and 4T APS

E20 Exam simulation

Review of basic electronics (focused for non-electronic students)
B01 photodiodes
B02 MOS noise
B03 eln basics

Industrial seminars with round tables
S01 MEMS Gyroscopes: design challenges and alternative approaches
Presenters: Vito Avantaggiati, Cristiano Marra, TDK-Invensense
The seminar is divided in two parts: the first one is a review of  open market specifications for MEMS gyroscopes, highlighting challenges that a system designer should face in his everyday work. Special attention is paid  to ZRO (Zero-Rate-Offset): the impact of quadrature and demodulation phase on offset stability is analyzed in detail.
The second part is related to a state of art technique to get offset stability, the force feedback. This technique uses a closed loop control to minimize the quadrature offset. Challenges and limitations of this technique will be reviewed in some details.

S02 MEMS clocks: small footprint timekeeping
Presenter: Paolo Frigerio, Politecnico di Milano
The seminar will introduce basic concepts of time-keeping devices for low-power applications. Details on the electromechanical resonator and on the single-transistor electronic circuit will be disucssed in light of the tight specifications of this application, with an outlook at market trends, which see capacitive MEMS resonators gradually replacing quartz-based piezoelectric elements.

S03 MEMS gyroscopes: design overview and market trends
Presenter: Stefano Facchinetti, ST Microelectronics
MEMS-based devices have experienced a rapid and massive growth in recent years, and can now be found in most of the products that we use every day. Inertial measurement units (IMU), including accelerometers and gyroscopes, have been among the first to be used, and now new products are entering the market – like MEMS-based microphones and micromirrors.
Nevertheless, the design of these products is not as consolidated as that of other electronic components, while market requirements are increasing very fast with respect to other “standard” devices. Moreover, the presence of the electro-mechanical component requires a strict interaction among various groups: analog designers, MEMS designers, technology specialists, packaging designers. These peculiarities of MEMS products make the system design phase both challenging and very exciting.
The aim of this short seminar is (i) to provide an overview of current MEMS market status and trends, (ii) give some guidelines for the design of the gyroscope electronics and (iii) show the main product specifications for gyroscope-based systems.

Exams Text and Solution (use them for practice during exam preparation)
03/02/2016 - Text and Solution
17/02/2016 - Text and Solution
11/07/2016 - Text and Solution
13/09/2016 - Text and Solution
27/09/2016 - Text and Solution
30/01/2017 - Text and Solution
16/02/2017 - Text and Solution
03/07/2017 - Text and Solution
18/07/2017 - Text and Solution
08/09/2017 - Text and Solution
31/01/2018 - Text and Solution
21/02/2018 - Text and Solution
28/06/2018 - Text and Solution
13/07/2018 - Text and Solution
09/03/2018 - Text and Solution
09/01/2019 - Text and Solution
31/01/2019 - Text and Solution
26/06/2019 - Text and Solution
19/07/2019 - Text and Solution
02/09/2019 - Text and Solution

MATLAB Scripts 
MATLAB routine #1 for sample Root Allan Variance visualization with different white noise, 1/f noise and offset drift. Enjoy...
MATLAB routine #2 for sample Photon Transfer Curve visualization as a function of different active pixel parameters. Enjoy...

Cadence Files
Cadence Tar file for Cad exercise on APS


Other Courses

Optoelectronic Systems and Digital Imaging

Professor: Giacomo Langfelder
Teaching Assistant: Paolo Minotti

The course covers the operation of some optoelectronic systems of general interest, starting from the characteristics of components and from the needs of the applications, in order to make the student is able to choose the most appropriate solutions, knowing the limits of use and performance theoretically achievable, and to design simple systems. Topics: 1) Systems for capturing digital images and resolution limits of optics and sensor. CCD and CMOS sensors; electronic signal reading; S / N ratio; dynamic range. Acquisition of color images. 2) Systems for the representation of colour images: LCD displays. Gamut. Backlight. 3) Systems for colour measurement: colour spaces and colour representation. Colorimeters and spectrophotometers. 4) Measurement of infrared signals: sensors. Applications to imaging and temperature measurement.

Slides of the course:
00 Introduction
01 Human Vision
02 Light Sources
03 Geometric Optics
04 Aberration Diffraction
05 FOV and DOF
06 Resolution MTF
07 Sensor MTF
08 Sensor Introduction
09 Active Pixel
10 HDR
11 4T and CDS
12 Color Acquisition
13 CFA and Demosaicking
14 System Noise
15 TFD
16 XYZ Color Space
17 Perceptual Color Spaces
18 Color Conversion
19 White Balance
20 Color Errors
21 Multispectral Imaging
22 Digital Imaging Simulations
23 Image Representation
24 Display Technologies
25 Vis+NIR Acquisition
26 Infrared Temperature Measurement
27 Auxiliary Subsystems

E01 Photodiodes Review
E02 Evaluation of the number of photons impinging on a camera pixel, starting from a generic scene
E03 Photography at known distances of known objects: choice of the camera parameters
E04 MOS and Noise Review
E05 Signal-to-Noise Ratio of a 3T APS for digital cameras
E06 Dynamic Range, choice of the ADC, maximum SNR of a 3T APS
E07 Timing issues in CMOS image sensors: maximum readout speed and rolling shutter readout
E08 Circuits for Correlated Double Sampling
E09 Photon Transfer
E10 Layered-junction sensor
E11 White Balance
E12 Color Instruments
E13 Summary Exercises
E14 Liquid-Cristal Display
E15 Image Sensor Design
E16 Temperature Monitoring
E17 Summary Exercises
Sample Exam


NEWS from the lab...
01-09-2019 congratulations to G. Mussi and co-authors for disseminating a brilliant article on MEMS real-time-clocks compensation vs temperature! Look for the TIE article "An Outlook on Potentialities and Limits in Using Epitaxial Polysilicon for MEMS Real-Time Clocks" on the IEEE website!

announcing the invited talk by Giacomo Langfelder at the upcoming IEEE Sensors conference 2019 in Montreal, Canada: "Frequency-modulated MEMS accelerometers for wide dynamic range and ultra-low consumption". Come join us in Quebec!

30-06-2019 Giacomo Langfelder presented an invited talk at the Transducers/Eurosensors 2019 Conference in Berlin, June 2019. The invited contribution title is "Frequency Modulated MEMS gyroscopes: recent developments , challenges and outlook". Check the upcoming proceedings on the IEEE website.

01-05-2019. Two presentations at the IEEE Inertial conference, three presentations at the IEEE MEMS conference, two presentations at the IFCS conference, and three presentations at Transducers... what a start for this 2019! Congratulations to all co-authors!

02-11-2018. A warm welcome to Paolo Frigerio and Leonardo Gaffuri, who have just started their PhD! Have three wonderful years of scientific research!

29-10-2018. A very complete article on the system-level development of frequency modulated gyroscopes has been accepted for publications in the IEEE Transactions on Industrial Electronics! Congratulations to all co-authors of "Fully Integrated, 406 μA, 5 ◦/hr, Full Digital Output Lissajous Frequency-Modulated Gyroscope"!