Performance improvement of an infrared scene generation chip by in-plane microstructures

Abstract

An infrared (IR) scene generation chip based on multi-layer thin film was demonstrated. Infrared radiation was efficiently converted from visible light energy through chip absorption. We proposed that the contradictive material parameter requirements aroused by high-spatial resolution and high-frame rate of the dynamic IR scene generator could be successfully solved by a periodical microstructure fabrication. The theoretical simulation results based on a semi-one-dimensional heat transfer model illustrated that the spatial resolution of the generated IR scene was improved using a microstructure with a low contact area ratio and high fill factor, while the thermal decay time of the chip was kept unaffected. Two infrared scene generation chips with different microstructures were fabricated by lithography and site-selective deposition. Measured by non-contact thermography, the chip with low microstructure contact area ratio (0.17) showed a higher spatial resolution (13.2 lp/mm) than that with high microstructure contact area ratio of 0.46 (8.0 lp/mm). Moreover, both chips had the same thermal decay time of 20 ms. The experimental results indicated that the proposed method is an effective and economic way to improve the performance of infrared scene generation chips.

Demonstration of thermal modulation using nanoscale and microscale structures for ultralarge pixel array photothermal transducers

“…In addition, due to the mature processing technology of infrared emitters, the pixel array achieved was sized 1300 × 1300, the apparent temperature was more than 489 K, and the frame rate was 50 Hz 23 . However, the 2D MEMS thin film emitter utilized in-plane microstructures to control the thermophysical properties 17 , 18 . It could not control the out-of-plane thermal diffusion, resulting in slow heat dissipation.…”

A Robust Infrared Transducer of an Ultra-Large-Scale Array

“…Thus, it contributed to larger temperature difference which was necessary to obtain higher imaging contrast. Moreover, the in-plane thermal conductivity of the PI layer could be controlled by optimizing the PI thickness and patterns [38,39]. The single pixel could be designed into various patterns.…”

“…The width of the frame around the double-S pattern also played an important role in the temperature and time response characteristics. We selected the same frame width of 7.5 µ m as the reported traditional soft transducer [38] for comparison. The single pixel was a square with a side length of 37 μm, and the inner pixel pattern The fabrication procedure of the traditional soft transducer was almost the same as that of the above robust one, other than oxidized silicon wafer was used to replace silicon wafer and there was no need to isotropically etch silicon.…”

“…The width of the frame around the double-S pattern also played an important role in the temperature and time response characteristics. We selected the same frame width of 7.5 µm as the reported traditional soft transducer [38] for comparison. The single pixel was a square with a side length of 37 µm, and the inner pixel pattern was a square with a side length of 22 µm.…”

Structure of Randomly Distributed Nanochain Aggregates on Silicon Substrates: Modeling and Optical Absorption Characteristics

“…These sparse and porous nanostructures can efficiently capture photons, and thus exhibit excellent optical properties [ 1 , 2 , 3 ]. Hence, optical absorbers based on nanoaggregate structures are widely used in microbolometers [ 4 ], photothermal converters [ 5 , 6 ], solar cells [ 7 , 8 ], and photocatalysis [ 9 ]. In addition, nanoaggregate structures show several desirable physical properties, such as low heat capacity, high specific surface area, and low density.…”