Ph.D Thesis

Ph.D StudentSocher Eran
SubjectInvestigation of Microelectrothermal Devices and their
Application in Uncooled Thermal Imaging
DepartmentDepartment of Electrical and Computer Engineering
Supervisor PROFESSOR EMERITUS Yael Nemirovsky


            In this research several novel devices applicable for use as uncooled micro-size thermal sensors are investigated and modeled. The temperature sensitive electrothermal behavior is explored and so are the ways to exploit it in the best way to realize the sensors.

            On the subject of thermoelectric sensing, novel design and fabrication methods developed in this research enabled the achievement of better results and integration fully compatible with CMOS technology. Arrays of such sensors were fabricated in CMOS technology using post-processing, along with integrated readout electronics, showing sensor NEP down to 0.12nW/√Hz.

            Microbolometers were given focus with novel distributed suspended structures that are integrated in standard CMOS technology. Arrays of such sensors were successfully realized in CMOS technology using novel micromachining techniques with integrated readout circuits using novel concepts of self heating compensation, showing device NEP of down to 30pW/√Hz.

            Discrete and distributed resistive electrothermal structures were studied, with emphasis on the points of instability, producing interesting results of conditions of instability and stability as a function of material properties and the electrical bias. Novel methods of modeling unstable distributed systems were investigated, that allow accurate simulation. Modeling calculations and prediction were successfully compared with measured results of fabricated devices.

            Another promising and completely new approach that was pursued is TMOS (Temperature sensitive MOS), which uses a MOS transistor as the temperature sensitive element, introducing readout capabilities in the sensing element and superior sensitivity that exceeds 6%/K in devices realized in CMOS-SOI technology, enabling achievable NEP of less than 1pW/√Hz and NETD of 10mK and less.