Uncooled thin film infrared imaging device with aerogel thermal isolation: deposition and planarization techniques

Abstract

We have successfully integrated a thermally insulating silica aerogel thin film into a new uncooled monolithic thin film infrared (E) imaging device. Compared to other technologies (bulk ceramic and microbridge), use of an aerogel layer provides superior thermal isolation of the pyroelectric imaging element from the relatively massive heat sinking integrated circuit. This results in significantly higher thermal and temporal resolutions. We have calculated noise equivalent temperature differences of 0.04-0.10 "C from a variety of PbXZryTi,,O3 (PZT) and PbxLa,~xZryTi,-yO, (PLZT) pyroelectric imaging elements in monolithic structures. In addition, use of aerogels results in an easier, less expensive fabrication process and a more robust device.Fabrication of these monolithic devices entails sol-gel deposition of the aerogel, sputter deposition of the electrodes, and solution chemistry deposition of the pyroelectric imaging elements. Uniform pyroelectric response is achieved across the device by use of appropriate planarization techniques. These deposition and planarization techniques are described.Characterization of the individual layers and monolithic structure using scanning electron microscopy, atomic force microscopy and B yer-Roundy techniques also is discussed.

Synthesis and biomedical applications of aerogels: Possibilities and challenges

“…ACCEPTED MANUSCRIPT 59 survival, and growth of neuron cells and therefore paved the way for implant applications. In another study by F. Sabri et al [43], the short and long-term in-vivo biocompatibility of PCSA in a Sprague-Dawley rat model have also been assessed.…”

Use of Stress To Produce Highly Oriented Tetragonal Lead Zirconate Titanate (PZT 40/60) Thin Films and Resulting Electrical Properties

“…T HE PbZrO 3 -PbTiO 3 (PZT) system is one of the most investigated materials systems for thin-film applications because of its potential for use in devices such as nonvolatile random access memories (NVRAM's), 1 field effect transistors, 2 uncooled pyroelectric detectors, [3][4][5] and actuators in microelectromechanical systems (MEMS). 6,7 The properties of interest vary by application; for example, a high dielectric constant is desired for capacitor applications, while large remanent polarization values are useful for memory devices.…”

Extrinsic size effect of pyroelectric response of ferroelectric films

“…The addition of intermediate thermal isolating layer was proposed for thermal decoupling of the film and substrate [28][29][30]38], and the effectiveness of the air gap was also considered [44,45]. With the same purpose integrated structures with PVDF/TrFE copolymer [30,32] and with SiO -aerogel 2 [41][42][43] thermal isolating layer were studied and then fabricated. The structures with mesoscopic porous silicon interlayer of low thermal diffusivity have been studied theoretically and experimentally [46,47,48].…”