Porous silicon samples were prepared by electrochemical etching method for different etching times. The structural properties of porous silicon (PS) samples were determined from the Atomic Force Microscopy (AFM) measurements. The surface mean root square roughness (σ rms) changes as function of porosity were studied, and the influence of etching time on porosity and roughness was studied too. U...

Damage free etching is required for the gate etching process in GaAs IC fabrication. While inductively coupled plasma (ICP) is thought to be the low damage etching technique, the degradation of DC characteristics was observed in our GaAs MESFETs. Threshold voltage shifts and Schottky barrier height is decreased. It was confirmed that the control of the antenna power (i.e. applied power to the u...

Recently, self-etching adhesive system has been introduced to simplify the clinical bonding procedures. It is less acidic compared to the phosphoric acid, thus there is doubt whether this system has enough bond strength to enamel. The purpose of this study was to investigate the influence of additional etching on the adhesion of resin composite to enamel. Ninety extracted bovine permanent anter...

Dry etching techniques employing ion beam induced surface reaction and the possibility of highly charged ion beam in dry etching are described, and the preliminary work on dry etching of GaAs using highly charged ion (HCI) is also presented. In usual dry etching, total etch rate is a summation of the physical sputtering rate, the chemical etching rate, and the ion-induced chemical etching rate....

Dynamic etching methods for fabricating fibre optic tips are explored and modelled. By vertically translating the fibre during etching by an HF solution under an organic protective layer, a variety of tip shapes were created. The probe taper lengths, cone angles and geometrical probe shapes were measured in order to evaluate the dynamic meniscus etching process. Fibre motion, etching rate, meni...

objectives: this study aimed to compare the microleakage beneath metallic brackets following two different methods of enamel preparation and light curing. materials and methods: a total of 120 bovine deciduous lower incisors were randomly divided into four groups of 30 teeth. the preparations were as follows: group i: acid etching + transbond xt primer + direct illumination, group ii: acid etch...

objectives: this study aimed to determine the effect of surface treatments such as tooth reduction and extending the etching time on microtensile bond strength (µtbs) of composite resin to normal and fluorotic enamel after microabrasion. materials and methods: fifty non-carious anterior teeth were classified into two groups of normal and fluorotic (n=25) using thylstrup and fejerskov index (tfi...

Aim: To assess the influence of dental etching on the shear strength of different glass ionomer cements. Methods: The crown of 60 bovine incisors was prepared to obtain a flat, smooth surface, were attached to a PVC tube and randomly divided into six groups: Group 1 – Riva Self Cure without etching; Group II – Riva Self Cure with pre-etching; Group III – Maxxion R without etching; Group IV – Ma...

Research and development in semiconducting silicon carbide (SiC) technology has produced significant progress in the past five years in many areas: material (bulk and thin film) growth, device fabrication, and applications. A major factor in this rapid growth has been the development of SiC bulk crystals and the availability of crystalline substrates. Current leading applications for SiC device...