Properties of CrSi2 Layers Obtained by Rapid Heat Treatment of Cr Film on Silicon

The changes in the morphology and the electrophysical properties of the Cr/n-Si (111) structure depending on the rapid thermal treatment were considered in this study. The chromium films of about 30 nm thickness were deposited via magnetron sputtering. The rapid thermal treatment was performed by the irradiation of the substrate’s back side with the incoherent light flux of the quartz halogen lamps in nitrogen medium up to 200–550 °C. The surface morphology was investigated, including the grain size, the roughness parameters and the specific surface energy using atomic force microscopy. The resistivity value of the chromium films on silicon was determined by means of the four-probe method. It was established that at the temperatures of the rapid thermal treatment up to 350 °С one can observe re-crystallization of the chromium films with preservation of the fine grain morphology of the surface, accompanied by a reduction in the grain sizes, specific surface energy and the value of specific resistivity. At the temperatures of the rapid thermal treatment from 400 to 550 °С there originates the diffusion synthesis of the chromium disilicide CrSi2 with the wave-like surface morphology, followed by an increase in the grain sizes, roughness parameters, the specific surface energy and the specific resistivity value.

Effects of Sputtering Current on Electrochemical Corrosion Characteristics of Nanoscale Chromium Films Deposited by Direct Current Magnetron Sputtering

Chromium coatings are often used for surface treatment of metals and alloys. In this study, nanoscale chromium coatings were deposited on 316L stainless steel by direct current magnetron sputtering. The effects of sputtering currents on electrochemical corrosion behavior of nanochromium coatings were investigated in 0.5 M H2SO4 + 2 ppm F− solution by electrochemical methods at room temperature. Results showed that the corrosion rates for nano-chromium coatings deposited at 0.25 A, 0.35 A, and 0.4 A were lower than bare steel by more than two orders of magnitude. The chromium coatings deposited at 0.25 A were inclined to degrade in the electrolyte after long-term immersion in the electrolyte, due to lesser coverage of passivity film on chromium coating. Moreover, the chromium coatings deposited at 0.3 A and 0.4 A exhibited excellent corrosion resistance due to formation of a continuous, compact and protective passive film.

Плавление и электромиграция в тонких пленках хрома

Chromium films with a thickness of 10–40 nm deposited onto silicon substrates by magnetron sputtering are subjected to the action of electric current induced by the tip of an atomic force microscope (AFM) cantilever in air under regular environmental conditions. The melting process at the nanoscale, electric field-induced migration of material, and the chemical reaction of chromium oxidation that occur in melt craters formed around the region affected by the current are investigated using optical and scanning electron microscopies, AFM, and Raman spectroscopy. The flow of melted material induced by electric current is accompanied by the formation and motion of an array of spherical nanoparticles in the melt crater along its periphery. We propose that the formation of nanodrop array at relatively low current densities can be explained by the chromium oxidation reaction and the surface tension of melted material on the silicon substrate.

EFFECT OF RAPID THERMAL TREATMENT CONDITIONS ON ELECTROPHYSICAL PROPERTIES OF CROMIUM THIN FILMS ON SILICON

Present paper is devoted the determination of the effect of the temperature of the process of rapid thermal treatment of chromium films on n-type conductivity silicon on their resistivity and contact properties of the interface. Chromium films of about 30 nm thickness were deposited by magnetron sputtering onto the surface of silicon substrates having a resistivity of 0.58 to 0.53 ohms×cm. The rapid thermal treatment was carried out in a heat balance mode by irradiating the back side of the substrates with non-coherent light flux in nitrogen ambient for 7 seconds. Quartz halogen incandescent lamps were used as the heating source. The temperature of the rapid thermal process ranged from 200 to 550 °C. The thickness of the chromium films was determined by raster electron microscopy. The surface resistance of the samples was measured by a four- probe method. The Schottky barrier height and the ideality factor were determined from I-V plots. It is shown that at the temperature of the rapid thermal process 400 °C a layer of chromium disilicide is formed, causing a sharp increase in the resistivity of chromium films to 1.2 mOhm×cm and the height of the Schottky barrier to 0.6 V. When the temperature of the rapid thermal process is further increased to 550 °C, the resistivity increases monotonically to 4.0 mOhm×cm due to the increase in the width of the interstitial boundaries increasing the scattering of charge carriers in the CrSi2 layers. It has also been shown that rapid thermal treatment of the Cr/Si structure at a temperature of 450–500 °C enables to obtain rectifying contacts with a barrier height of 0.615 V and an ideality factor of 1.1. The results obtained can be used in the technology of integrated electronics products containing Schottky contacts as well as thin film resistors.

A microscope image processing method for analyzing TLIPSS structures

The paper describes a method for processing microimages of thermochemical laser-induced periodic surface structures (TLIPSS) to quantify their structural order and defects. Results of its application for the analysis of microimages of periodic structures formed in 30-nm chromium films by an astigmatically focused femtosecond Gaussian laser beam have been presented. Dependences of the relative area of the beam-modified region, the area of defects, and the ordering of the periodic structures on the scanning speed and the writing beam power have been obtained.