Study of the Absorption of Electromagnetic Radiation by 3D, Vacuum-Packaged, Nano-Machined CMOS Transistors for Uncooled IR Sensing

Abstract

There is an ongoing effort to fabricate miniature, low-cost, and sensitive thermal sensors for domestic and industrial uses. This paper presents a miniature thermal sensor (dubbed TMOS) that is fabricated in advanced CMOS FABs, where the micromachined CMOS-SOI transistor, implemented with a 130-nm technology node, acts as a sensing element. This study puts emphasis on the study of electromagnetic absorption via the vacuum-packaged TMOS and how to optimize it. The regular CMOS transistor is transformed to a high-performance sensor by the micro- or nano-machining process that releases it from the silicon substrate by wafer-level processing and vacuum packaging. Since the TMOS is processed in a CMOS-SOI FAB and is comprised of multiple thin layers that follow strict FAB design rules, the absorbed electromagnetic radiation cannot be modeled accurately and a simulation tool is required. This paper presents modeling and simulations based on the LUMERICAL software package of the vacuum-packaged TMOS. A very high absorption coefficient may be achieved by understanding the physics, as well as the role of each layer.

Toward an Accurate IR Remote Sensing of Body Temperature Radiometer Based on a Novel IR Sensing System Dubbed Digital TMOS

“…The micro-machined thermally insulated transistor has very low thermal mass and very low thermal conductivity. The absorbed photons increase the TMOS temperature and modify the current–voltage characteristics, and since the transistor is operated at a subthreshold region, its I-V characteristics are highly dependent on temperature (exponentially), therefore a highly sensitive sensor is achieved [ 10 , 11 , 12 , 13 , 14 , 15 , 16 , 17 ].…”

Editorial for the Special Issue “MEMS Packaging Technologies and 3D Integration”

“…MEMS devices tend to be packaged in chip-scale, or, namely, zero-level packaging as fabrication technologies advance in place of conventional package of a commercial product such as DIP (Dual Inline Package). For certain MEMS products, vacuum packaging has been achieved with zero-level packaging approaches [ 1 , 2 ]. Such a MEMS packaging has mainly been realized by bonding techniques with joint materials such as metals, polymers, etc.…”