Characterization of transfer-bonded silicon bolometer arrays

Abstract

In this paper we present the design, fabrication and characterization of arrays of boron doped polycrystalline silicon bolometers. The bolometer arrays have been fabricated using CMOS compatible wafer-level transfer bonding. The transfer bonding technique allows the bolometer materials to be deposited and optimized on a separate substrate and then, in a subsequent integration step to be transferred to the read-out integrated circuit (ROIC) wafer. Transfer bonding allows thermal infrared detectors with crystalline and/or high temperature deposited, high performance temperature sensing materials to be integrated on CMOS based ROICs. Uncooled infrared bolometer arrays with 18x18 pixels and with 320x240 pixels have been fabricated on silicon substrates. Individual pixels of the arrays can be addressed for characterization purposes. The resistance of the bolometers has been measured to be in the 50 kW range and the temperature coefficient of resistance (TCR) of the bolometer has been measured to be -0.52 %/K. The pixel structure is designed as a resonant absorbing cavity, with expected absorbance above 90%, in the wavelength interval of 8 to 12 mm. The measured results are in good agreement with the predicted absorbance values.

Wafer-level heterogeneous 3D integration for MEMS and NEMS

“…12a [18], and 320x240 pixels Si/SiGe quantum-well infrared bolometers arrays as shown in Fig12b [8,12,13]. Figure 12.…”

“…Using Via-Last Processes Demonstrations of via-first heterogeneous integration technologies for MEMS and NEMS include infrared bolometer arrays [8][9][10][11][12][13][14], arrays of tilting and piston-type micro-mirrors [14][15][16][17][18], micro-pirani vacuum gauges [19], RF MEMS [1,20] and many more devices [1]. For most of these applications, adhesive wafer bonding has been used to join the MEMS and the IC wafers.…”

Heterogeneous integration for optical MEMS

“…Fig. 5 shows an infrared bolometer array with a pixel size of 40 µm x 40 µm and vias with a diameter of 3 µm [5]. Fig.…”

“…Via-last heterogeneous integration processes based on adhesive wafer bonding [3,4] have been implemented for a number of MOEMS and MEMS devices, including infrared bolometer arrays [5,6], mono-crystalline silicon micro-mirror arrays [7][8][9] and radio frequency meta-material surfaces [10]. Fig.…”

Micromechanical Process Integration and Material Optimization for High Performance Silicon-Germanium Bolometers

“…Emerging very large scale heterogeneous 3D integration technologies for combining high-performance MEMS (Microelectromechanical System) on top of CMOS-based integrated circuit (IC) wafers provide opportunities to decouple the fabrication of the CMOS circuits and the manufacturing of the MEMS [18][19][20][21][22][23]. Thus, for IR bolometer applications the thermistor material can be manufactured and optimized using high-quality epitaxial deposition processes at elevated temperatures.…”