Development of thermoelectric detectors on the basis of higher manganese silicide (HMS) films

Abstract

It is known that HMS - MnSi/sub 1.71-1.75/ is an anisotropy degenerative semiconductor and has figure-of-merit Z=0.7x10/sup -3/ K/sup -1/ in the range T=400-1000K. It is used in production of high effective thermoelectric converters. Besides, HMS has high chemical and radioactive resistance. At first in the world practice, we developed and created the technology of production of poly crystalline MnSi/sub 1.71-1.75/ thin films on the silicon substrates. These MnSi/sub 1.71-1.75/ films have better thermoelectric and photoelectric parameters than MnSi/sub 1.71-1.75/ bulk single crystals. We also created the thermoelectric converters and the detectors of infrared radiation on basic MnSi/sub 1.71-1.75/ films with thickness d=1-20 /spl mu/m. The phase and structural analyses of MnSi/sub 1.71-1.75/ films were carried out by X-ray reflection, electron diffraction and transmission electron microscopy methods. The analyses demonstrated that the MnSi/sub 1.71-1.75/ films have a polycrystalline columnar structure of crystallites the grown crystallites had the normal orientation with respect to the Si-substrate. The main parameters of the HMS thermoelectric converters and HMS IR-detectors were studied at T=400-1000 K. These devices are stable and have the sensitivity S=500-1000 /spl mu/V/W the thermoelectric power /spl alpha/=150-250 /spl mu/V/K and the response time /spl tau//spl les/10/sup -6/ s at T=223- 1000 K. It is notified that the technology of production of MnSi/sub 1.71-1.75/- films and MnSi/sub 1.71-1,75/device is cheap and ecologically clean. Moreover, the devices were processed by ultrasonic at frequency f=3.5 MHz with intensity 1 W/cm/sup 2/ for 45 minutes at T=300 K. As a result, the thermo electromotive force has been increased significantly from the above range to /spl alpha/=360 - 400 /spl mu/V/K.