84418 - Advanced Solid-State Sensors M

Course Unit Page

Academic Year 2018/2019

Learning outcomes

The learning outcome of this course is that of illustrating the functioning principles of the most important categories of solid-state sensors. The students will learn about sensors realized with process techniques used in Microelectronics and Micro-Electro-Mechanics Systems (MEMS). For each sensor, the physical effect, the model used for its characterization and the technological aspects used for the overall realization will be analysed. During the lab practice, a number of tools suitable for the numerical simulation of the sensors proposed in the course will be shown. Competencies: (general) to have critical understanding of technical and scientific tools; to be able to select and apply numerical TCAD tools; communication skills; to be able to work in an international context; (specific) to understand the methods for investigating advanced solid-state sensors; to determine the important microscopic and macroscopic parameters involved in the functioning of solid-state sensors; to perform numerical analyses of solid-state sensors. Detailed contents: introductory part where the definition of the main classes of solid-state sensors is given; main physical effects in solid-state sensors. Elementary optical sensors (photo resistor, photodiode, photo capacitor); operation of charge-coupled devices (CCD). Performance analysis of solid-state video cameras; piezo resistive sensors of acceleration and pressure; piezoelectric accelerometer; vertical and lateral capacitive accelerometers; thermal sensors: integrated thermopile sensors; semiconductor-junction temperature sensors; proportional-to-absolute-temperature sensors (PTAT); magnetic sensors: Hall plates; differential-amplification magnetic sensors (DAMS); MAGFET and dual-drain MAGFET; vertical and lateral magneto transistors. Energy-efficient gas sensors based on SOI CMOS technology.

Course contents

Requirements/Prior knowledge

Prerequisite for the understanding of the arguments is the knowledge of the key concepts on electron devices and circuits and basic concepts of mathematics and physics acquired from earlier courses. In particular, the student should be able to analyze the behaviour of simple analog circuits using diodes, MOSFETs, BJTs or OPAMPs both in stationary and transient conditions.

Fluent spoken and written English is a necessary pre-requisite: all lectures and tutorials, and all study material will be in English.

Course contents

Course introduction: new technologies for integrated solid state sensors (Microelectronics and Micro-Electro-Mechanics Systems), definition and classification of sensors (the sensor cube by Middelhoek and Noorlag). Definition of noise signals in the time domain. The noise power spectrum. Definition of noise signals in frequency domain. Description of noise models for resistors, diodes, MOSFETs, BJTs and OPAMPs. Brief description on the absorption of radiation in a semiconductor material. Elementary optical sensors: photoresistor, photodiode (in dc and pulsed regime), MOS photocapacitor, MOS and bipolar phototransistors. Structure and operation of charge-coupled devices (CCD); linear-array and full-frame image sensors. Performance analysis of solid-state video cameras. Noise contributions to image sensors. Introduction to the elasticity theory; description of the mechanical deformation of cantilever beams and membranes; equations of the distribution of the reaction forces and moments with general loads. Piezoresistive sensors of acceleration and pressure. Piezoelectric accelerometer. Vertical and lateral capacitive accelerometers. Noise contributions in piezoresistive sensors. Introduction to the thermoelectric and thermoresistive effects. Thermal sensors: integrated thermopile sensors; semiconductor-junction temperature sensors; proportional-to-absolute-temperature sensors (PTAT). Introduction to Hall and magnetoresistance effects. Magnetic sensors: Hall plates; differential-amplification magnetic sensors (DAMS); MAGFET and dual-drain MAGFET; vertical and lateral magnetotransistors. Energy-efficient micro-hotplates for resistive and infra-red gas sensors based on SOI-CMOS/MEMS technology.

In the lab practice, a number of tools suitable for the numerical simulation of the sensors will be shown and used to illustrate the functioning principles of solid-state sensors based on silicon devices. For each sensor, the physical effect, the model used for its characterization and the technological aspects used for the overall realization will be discussed.

Readings/Bibliography

S. M. Sze “Semiconductor Sensors” , Wiley Interscience.

S. D. Senturia "Microsystem Design", Springer, 2001, ISBN 978-1-4757-7458-0

M. Rudan, "Physics of Semiconductor Devices", Springer, Springer, 2018. ISBN 978-3-319-63153-0

Teaching methods

The course consists of classroom lectures in which the physical effects and the models used for the characterization of the solid-state sensors are presented, the technological aspects used for the overall realization are discussed, the circuit solutions adopted to optimize the performance and the signal-to-noise answer are proposed. The theoretical presentation of the topics is followed by several laboratory activities devoted to the TCAD simulation of sensor aiming to acquire the method for analyzing and designing simple devices.

Assessment methods

Learning assessment is done through a final exam that ensures acquisition of knowledge and expected skills. The student will carry out an oral test.

The oral test consists in 3 questions, one to verify the ability to analyze circuits or devices used in integrated sensors, the second covering the main theoretical instruments for the analysis of the physical properties of materials or devices suitable for the transduction effect, and a third one involving the noise analysis of the semiconductor devices and circuits. To obtain a passing grade, the student must demonstrate the capacity to manage the key concepts illustrated in the course program. The duration of the oral test is about 60 minutes.

To attend the exam it is required to register via Almaesami. Those who do not succeed to register by the deadline are required to promptly notify the problem at the Secretary's office.

Teaching tools

Teaching material: slides, notes and examples of TCAD simulation setups will be available to students via the distribution list or in https://www.unibo.it/sitoweb/susanna.reggiani/contenuti-utili

Office hours

See the website of Susanna Reggiani