TiAl-based Ohmic Contacts to p-type 4H-SiC

This paper describes successfully formed ohmic contacts to p-type 4H-SiC based on titanium-aluminum alloys. Four different metallization structures were examined, varying in aluminum layer thickness (25, 50, 75, 100 nm) and with constant thickness of the titanium layer (50 nm). Structures were annealed within the temperature range of 800°C - 1100°C and then electrically characterized. The best electrical parameters and linear, ohmic character of contacts demonstrated structures with Al layer thickness equal or greater than that of Ti layer and annealed at temperatures of 1000°C or higher

Influence of the deposition process parameters on electronic properties of BN films obtained by means of RF PACVD, Journal of Telecommunications and Information Technology, 2007, nr 3

This work presents results of investigations of electronic properties of undoped boron nitride (BN) films produced on Si substrates in the course of radio frequency (rf) PACVD process with boron triethyl (C2H5)3B as the boron source. The influence of the deposition process parameters on thickness and electronic properties (resistivity r, dielectric strength EBR) of BN films based on ellipsometry and I-V curve measurements at room temperature is studied. The obtained results show that proper selection of deposition process parameters allows BN layers with the required thickness and advantageous values of r and EBR to be fabricated. BN becomes therefore an interesting material for microelectronics applications

Effect of Sample Elevation in Radio Frequency Plasma Enhanced Chemical Vapor Deposition (RF PECVD) Reactor on Optical Properties and Deposition Rate of Silicon Nitride Thin Films

In this paper we investigate influence of radio frequency plasma enhanced chemical vapor deposition (RF PECVD) process parameters, which include gas flows, pressure and temperature, as well as a way of sample placement in the reactor, on optical properties and deposition rate of silicon nitride (SiNx) thin films. The influence of the process parameters has been determined using Taguchi’s orthogonal tables approach. As a result of elevating samples above the electrode, it has been found that deposition rate strongly increases with distance between sample and the stage electrode, and reaches its maximum 7 mm above the electrode. Moreover, the refractive index of the films follows increase of the thickness. The effect can be observed when the thickness of the film is below 80 nm. It has been also found that when the deposition temperature is reduced down to 200 °C, as required for many temperature-sensitive substrate materials, the influence of the substrate material (Si or oxidized Si) can be neglected from the point of view of the properties of the films. We believe that the obtained results may help in designing novel complex in shape devices, where optical properties and thickness of thin plasma-deposited coatings need to be well defined

Oxidation Process of SiC by RTP Technique

score: 0collation: 529-53

Tailoring Refractive Index and Adlayer Sensitivity of an Optical Fiber Fabry-Perot Interferometer by a Thin Layer Deposition

This work discusses the capability of tailoring sensitivity of an optical-fiber-based Fabry–Perot interferometric (FPI) sensor to changes in refractive index (volume) and formation of a layer on the sensor surface (adlayer). A simple single-layer approach shows some disadvantages, especially when refractive index (n) sensing is considered, e.g., there is no shift of the interference pattern in the wavelength domain. The considered FPI sensor is based on two transparent thin films deposited on a single-mode optical fiber’s end face. As the first layer, a high-n titanium oxide (TiO2) was chosen. We show that addition of a second layer of lower n results in the blueshift of spectral pattern with external n (next). Moreover, when an additional layer, e.g., biological one, is formed, a redshift of the pattern appears, what is in contrary to the shift induced by the increase of next. Numerical analysis as well as experiments show that a wide range of materials (with different n and thickness) can be applied as the second layer, influencing both volume and adlayer sensitivities. We have found that when the second layer thickness is tailored to obtain a well spectrally defined pattern, high n contrast between the layers increases the volume sensitivity, while for the moderate n contrast the adlayer sensitivity of the FPI can be enhanced. The proposed approach shows large tuning capability towards desired application, as well as can be easily introduced to large-scale sensor manufacturing. </p