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3. The design of the sensor element with integrated piezoelectric and strain-resistant films 
Figure 1 shows the model of the sensitive element of the sensor for measuring alternating and static 
pressure, built on the basis of silicon poles with formed platinum tracks integrated by piezoelectric 
capacitive structures with semiconductor strain gages [10 - 12]. 
 
Figure 1
. Model of the sensitive element of the pressure sensor. 
Capacitor piezoelectric structures are formed in the center of the sensitive element, on the periphery of 
the hard center. Compression and expansion strain gages are located along the perimeter of the 
membrane in the zones of greatest deformation. 
They are made according to the developed technology of plasma-chemical deposition of 
polycrystalline silicon. The thermo-resistor is formed by ion implantation. 
Further fabrication of the crystal of the sensing element is carried out by anodic splicing of silicon 
with glass at temperatures above 500 °C and the voltage applied to the structure, of the order of 
several hundred volts. This will inevitably lead to a reorientation of thin PZT films polarization. As 
thin piezoelectric films, it is advisable to use zinc oxide or aluminum nitride. 
Textured AlN piezoelectric films used as a device layer were obtained by ion-beam sputtering of an 
target from Al in an argon-nitrogen mixture in a modernized ion-beam sputtering unit with a residual 

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SPbOPEN 2019
Journal of Physics: Conference Series
1410 (2019) 012230
IOP Publishing
doi:10.1088/1742-6596/1410/1/012230
3
pressure of 3 to 5 ∙ 10
-5
Pa to eliminate the reaction gas gettering which manifests itself during 
magnetron sputtering as a result of plasma radiation. When ion-beam sputtering, the target and the 
substrate are outside the plasma, which qualitatively improves the structure properties [13]. 
The substrate temperature was varied from 150 to 350 °C. Textures with satisfactory properties are 
formed at 350 °C. The pressure of the working mixture in the vacuum chamber was maintained in the 
range from 1 to 3 ∙ 10
-3
Pa in the ratio of gases Ar : N2 = 1 : 1. When reducing the argon percentage, a 
decrease in the rate of the target material sputtering and the deterioration of the deposited film 
properties are observed. This is due to the chemical activity of nitrogen entering into the compound 
with the target material on its surface, and the insufficient energy of the bombarding ions compared 
with the kinetic energy of argon ions for intensive ejection of atoms and atoms conglomerates 
(clusters) from the target [13]. 
The disadvantages of the ion-beam method of sputtering AlN include the relatively low reproducibility 
of the resulting films properties and the structures defectiveness due to knocking out clusters (atoms 
conglomerates) that degrade the film texture.
ZnO thin films with piezoelectric properties were obtained by reactive HF-magnetron target sputtering 
from Zn (99.9 %) in an Ar + 65% O
2
gas mixture at a chamber pressure of 1 to 3 ∙ 10
-3
Pa. The 
substrate temperature was 220 °C, the RF discharge power was 100 W. The use of RF magnetron 
target sputtering from Zn (99.9 %) instead of DC sputtering is caused by the “poisoning” of the target 
with oxygen and the formation of a surface dielectric layer contributing to the appearance of a surface 
charge reducing the sputtering rate. In addition, when HF target sputtering ZnO, it often cracks as a 
result of overheating. The exclusion of thermo-mechanical stresses was carried out by carrying out 
heating and cooling in both cases at a rate of not more than 3 °C/min. Sputtering of piezoelectric 
structures in combination with the spent silicon technology for obtaining strain gages can be carried 
out both before the formation of strain gages and after. 
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