K.V. Korsak1, P.E. Novikov2, I.Yu. Lovshenko3, V.R. Stempitsky4, Dao Dinh Ha5, Tran Tuan Trung6, D.S. Liauchuk7, A.E. Zhamoit8, A.I. Zanko9, Ya.A. Solovjov10

1–4 Belarusian State University of Inforcatics and Radioelectronics (Minsk, Belarus)
5, 6 Le Quy Don University of Science and Technology (Hanoi, Vietnam)
7–10 JSC «INTEGRAL» – «INTEGRAL» Holding Managing Company (Minsk, Belarus)
1 k.korsak@bsuir.by, 2 p.novikov@bsuir.by, 3 lovshenko@bsuir.by, 4 vstem@bsuir.by, 5 daodinhha@lqdtu.edu.vn, 6 trantuantrungcan@gmail.com, 7 DLevchuk@integral.by, 8 AZhamoit@integral.by, 9 AZanko@integral.by, 10 JSolovjov@integral.by

The design of uncooled thermal detectors of the bolometric type (microbolometers) requires precise control of the geometrical parameters of the structure (layer thicknesses and topology) to achieve optimal thermal characteristics. Non-optimal choices for these parameters lead to degradation of key performance indicators: reduced sensitivity, increased response time, and decreased device energy efficiency. Therefore, a systematic investigation of the influence of functional layer thicknesses and pixel topology on performance is of particular importance.

Objective – to determine, through computer modeling, the extent of the influence of structural and topological parameters of the microbolometer pixel's constituent layers on its thermodynamic and mechanical characteristics.

Computer modeling revealed that the dielectric layers have a minor influence on heat capacity and thermal conductivity, as well as a minimal effect on structural deformation and time constant. Increasing their thickness results in a proportional increase in both thermal conductivity and heat capacity, leading to no discernible change in the time constant. However, the lower passivation layer significantly influences the mechanical deformation of the microbolometer pixel, effectively acting as the membrane's supporting layer. Increasing this layer's thickness from 0,5 to 1,0 times of its nominal value reduces the maximum absolute Z-axis deflection by over 60%.

The thermosensitive and conductive layers exert the greatest influence on the structure's thermal conductivity and heat capacity, respectively, as their materials exhibit the highest thermal conductivity (G) and heat capacity (C) values among the materials used.
The microbolometer pixel's leg width has the most significant impact on thermal conductivity (G). Increasing the leg width enhances the influence of the conductive film on thermal conductivity, subsequently reducing the structure's thermal resistance and leading to a proportional decrease in the time constant (τ).

The obtained data can be used in the development of microbolometers with improved mechanical reliability and a tailored thermal response.

1. Morozov A.M. i dr. Medicinskoe teplovidenie: vozmozhnosti i perspektivy metoda. Medicinskij sovet. 2022. T. 16. № 6. S. 256–263 (in Russian).
2. Chaturvedi A., Kumar P., Rawat S. Proposed noval security system based on passive infrared sensor. 2016 International Conference on Information Technology (InCITe)-The Next Generation IT Summit on the Theme-Internet of Things: Connect your Worlds. 2016. P. 44–47.
3. Gaur A. et al. Fire sensing technologies: A review. IEEE Sensors Journal. 2019. V. 19. № 9. P. 3191–3202.
4. Yadav P. V. K. et al. Advancements of uncooled infrared microbolometer materials: A review. Sensors and Actuators A: Physical. 2022. V. 342. P. 113611.
5. Lee H.J. et al. Wide-temperature (up to 100 C) operation of thermostable vanadium oxide based microbolometers with Ti/MgF2 infrared absorbing layer for long wavelength infrared (LWIR) detection. Applied Surface Science. 2021. V. 547. P. 149142.
6. Kolovsky A.A. Computer Modeling of MEMS Components. Problems of Development of Promising Micro and Nanoelectronic Systems. 2008. V. 1. P. 398.
7. MATLAB [Electronic resource]. URL: https://www.mathworks.com/products/matlab.html (date of access: 05.05.2025).
8. Cadence | Computational Software for Intelligent System Design [Electronic resource]. URL: https://www.cadence.com (date of access: 05.05.2025).
9. Mikrobolometr v dvuh spektral'nyh diapazonah [elektronnyj resurs]. URL: https://astrohn.ru/2018/02/09/microbolometr/(Data dostupa: 05.05.2025) (in Russian).
10. The Materials of Uncooled Infrared Detectors [Electronic resource]. URL: https://www.gst-ir.net/news-events/infrared-knowledge/ 355.html (date of access: 05.05.2025).
11. Proizvodstvo teplovizionnyh detektorov [elektronnyj resurs]. URL: https://astrohn.ru/production/proizvodstvo-teplovizionnyh-detektorov/ (Data dostupa: 05.05.2025) (in Russian).