Study of new materials and composites based on porous silicon is of great interest for electronics and microelectronics industry. Functional characteristics of structured layers are closely associated with their morphology properties and treatment conditions correspondently. In this work a porous silicon layers formed by metal-assisted chemical etching (MACE) with the use of gas adsorption-desorption method, scanning electron microscopy (SEM) and fractal geometry have been examined. Specific surface area given by multi-point BET method was about of 7 m2/g and 13 m2/g for n-Si and p-Si specimens correspondently. Surface fractal dimension Ds was estimated for p-type mesoporous silicon from BET results using Neimark’s thermodynamic approach, the value is Ds=2.86. “Slit islands” Mandelbrot’s algorithm was applied for analysis of SEM images and calculations of surface fractal dimension Ds, computation gives Ds = 2.52 for n-Si sample and Ds = 2.84 for p-Si sample. The study testified the fractal nature of porous layers formed by MACE and exhibits correlation between different methods of fractal dimension estimation. The results can be applied for improvement of methods of structured solids characterization.
The results of development of driving setup for micromechanical friction vacuum gauge are presented. For driving of the micromechanical transducer the saw-tooth signal was used because of its good repeatability and possibility of automatic operation. Specialized switching card for resonator driving and output signal processing was developed and implemented. Experimental setup consists of PC, electric switching card and oscilloscope was used to explore damped and overdamped oscillations. The study exhibits stable repeatability of driving procedure. Resonator eigenfrequency agrees with calculated value and confirms that oscillations correspond to the main mode. The results can be applied for creation of micromechanical friction vacuum gauges.