V. Yu. Zerov

Vanadium oxide films with improved characteristics for ir microbolometric matrices

Vanadium oxide (VOx) films intended for use in uncooled IR microbolometric matrices were deposited by reactive magnetron sputtering on silicon substrates. Optimum deposition conditions were determined, which provide for the obtaining of films possessing a current 1/f noise level 3–10 times lower, extended dynamic range, and increased working temperature interval. It was found that the 1/f noise level of the VOx films depends on the VO2 phase content and grain size. It is suggested that the observed 1/f noise is caused by the martensite transformation characteristic of the semiconductor-metal phase transition in VO2.

Calculational modelling of the main characteristics of an uncooled linear microbolometer array

This paper describes a technique for calculating the main characteristics of an uncooled linear microbolometer array. It presents the results of the calculations that were carried out, discusses them, and compares them with the experimental values. It shows that a detectivity of about 10 9 cm Hz 1/2/W can be achieved in microbolometers with a detector area of 46×46 µm at a frequency of 10 Hz and that they can be used as a basis for creating a linear 64-element array of a scanning thermal viewer with frame rate of as much as 1.6 Hz having NETD=0.06 K.

Comparative investigations of the bolometric properties of thin film structures based on vanadium dioxide and amorphous hydrated silicon

A choice of sensitive element material for uncooled microbolometric array dependents on the ultimate array parameters to a great extent. This paper presents the results of studies of sandwich and planar bolometric structures based on aSi:H and VO2 films accordingly. The aSi:H films were fabricated by plasmachemical vapor-phase deposition and VO2 films were prepared by reactive magnetron ion-plasma sputtering. Sandwich structures with area 100 X 100 micrometers have a resistance of 20 k(Omega) and temperature coefficient of resistance (TCR) of approximately equals 2%/K at 25 degree(s)C. Planar structures with operating section dimensions of 100 X 70 micrometers have TCR of 2.9%/K at the same resistance. The methods of contact noise reduction are found for both type structures. Sandwiches constructed to act as an optical cavity absorb 80% of radiation at 8 micrometers wavelength. It is shown that the planar structures absorption of 50 - 80% can be reached in the 8.5 - 10 micrometers band.

Antenna-coupled microbolometers

This paper analyzes the development trends of devices and processes for fabricating antenna-coupled microbolometers for the IR, submillimeter, and millimeter ranges. Depending on the problem to be solved, these thermal detectors can be self-contained or can be built into linear or two-dimensional arrays and can operate at temperatures of 300, 78, and 4 K. The temperature determines the choice of material of the thin-film heat-sensitive element—metal, semiconductor, high-temperature or classical superconductor. The planar antennas used in these detectors provide efficient reception of radiation in the specified spectral range. The achievable parameters and examples of the use of antenna-coupled microbolometers are discussed.

Bolometric properties of silicon thin-film structures fabricated by plasmachemical vapor-phase deposition

A method of fabricating uncooled thermally sensitive sandwich structures based on amorphous hydrated silicon films is discussed and experimental results are reported. The structures have an area of 10−4 cm2, a resistance of ≅10 kΩ, and a temperature coefficient of resistance ≃2%/K. At 30 Hz and a current of ≃1 μA, the excess noise exceeds the thermal resistance noise by a factor of 1.7.

Development of 65 X 1 uncooled membrane-type microbolometer array

This paper presents the structure and technology of 65- elements linear array of membrane type microbolometers, and the research results of its properties. DC biased microbolometers with VOx thermosensitive layer have detectivity of 5x107 cm/Hz1/2W at 12.5 Hz at 12.5 Hz frequency, and response time of 3 ms. The ways of improvement of developed linear array sensitivity are planed.