The main objective of the project was to fabricate a vertical Gate All Around (GAA) p-i-n doped Tunneling Field Effect Transistor (TFET) device for which attaining precise nanopillar structure were needed, to be optimized and achieved. This paper specifically focused on fabrication of Nano pillar on Silicon wafer using Hydrogen Silsesquioxane (HSQ). Initially we experimented with two methods Plasma Asher and AMAT Etch chamber. We have chosen HSQ resist for patterning high-resolution 100 nm circular dot structures for the fabrication of densely packed suspended vertical Si Nano pillars. This provides high etching resistivity of HSQ and better convenience of pattern transfer and selectivity from resist to various materials. IN addition, epitaxial semiconductor Si wafers with different semiconductor layers have been directly implemented to render nanopillars with self-aligned and well-defined homo or hetero junction properties. These structures may be used to analyze evidence of the primary design of devices such as vertical surround Gate field effect transistors.

Background: We evaluated the effect of phosphoric acid etching on microleakage of two current self-etching adhesives on enamel margins in comparison to a conventional total- etch system. Methods: Sixty buccal class V cavities were made at the cemento-enamel junction with beveled enamel margins of extracted human premolar teeth and randomly divided into five groups (12 specimens in each group). Group 1 was applying with Clearfil SE bond, Group 2 with 35% phosphoric acid etching of enamel margins plus Clearfil SE bond, Group3 with I bond, Group 4 with 35% phosphoric acid etching of enamel margins plus I bond and Group5 with Scotchbond multi-purpose. All groups restored with a composite resins. After 24 hours storage with 100% humidity, the samples were thermocycled, immersed in a dye solution and sectioned buccoligually and enamel margins microleakage were evaluated on a scale of 0 to 2. Results: The differences between Groups 1 & 3 and Groups 3 & 4 were significant (P<0.05) but no significant differences between Groups1 & 2 or 1 & 5 were observed. Conclusion: The findings suggest that all-in-one adhesive systems need pre-etching enamel margins with phosphoric acid for effectively seal.  

Objective: path of microleakage between the enamel and adhesive potentially al-lows microbial ingress that may consequently cause enamel decalcification. The aim of this study was to compare microleakage of brackets bonded either by laser or acid etching techniques.Material and Methods: The specimens were 33 extracted premolars that were divided into three groups as the acid etching group (group 1), laser etching with Er: YAG at 100 mJ and 15 Hz for 15s (group 2), and laser etching with Er: YAG at 140 mJ and 15 Hz for 15s (group 3). After photo polymerization, the teeth were subjected to 500 thermal cycles. Then the specimens were sealed with nail varnish, stained with 2% methylen blue for 24hs, sectioned, and examined under a stereomicroscope. They were scored for marginal microleakage that occurred be-tween the adhesive-enamel and bracket-adhesive interfaces from the occlusal and gingival margins. Data were analyzed with the Kruskal- Wallis test.Results: For the adhesive-enamel and bracket-adhesive surfaces, significant differences were not observed between the three groups.Conclusion: According to this study, the Er: YAG laser with 1.5 and 2.1 watt set-tings may be used as an adjunctive for preparing the surface for orthodontic bracket bonding.

in this-article, behavioral analysis of Silicon anisotropic etching in Tetramethyl Ammonium Hydroxide (TMAH) water solution is investigated. Therefore, silicon Etching process is performed with different concentration of 5, 10, 15 and 25 wt. %, and in the various temperatures of70, 80 and 90°C. Measured results show that the etching rate intensifies by increasing the solution temperature, but it decreases with increasing in TMAH concentration greater than 10 wt. %. a maximum etching rate on the p-type Si (100) surface; reaches a value of 6211m1h at a solution temperature of 90oC and TMAH concentration of 10 wt. %. SEM images show that the silicon surface lumps appear like small pyramid-shaped hillocks in which form and distribution on silicon surface is completely random The surface roughness increases with decreasing of TMAH concentration and much smoother silicon surface can be observed for higher concentration. Moreover, the maximum <100>/<111> etch rate ratio is 10.6 obtained in 10 wt. %TMAH. This concentration of TMAH has the minimum undercut.

Introduction: Fissure sealant is a safe and effective method to prevent dental caries, especially occlusal surface caries of posterior teeth. Many investigations have been carried out to evaluate sealant efficacy on caries prevention. The purpose of this study is the effect of total and self – etching systems on micro leakage of pit using fissure sealant and flow composite in permanent teeth. Materials & Method: Sixty non-caries maxillary premolar were chosen to represent the anatomy fissure for fissure sealant. No invasive technique was used. The premolars were randomly divided into 4 groups of 15. . Group A: Acid etch + single bond + flow composite . Group B: Acid etch + Fissure sealant. Group C: Self-etch + flow composite. Group D: Self-etch + Fissure sealant.The sample was thermo cycled for 500 times at 5-55 degrees Celsius and was immersed 1n %2 basic Fuchin for 24 hours. Then, all teeth were embedded in clean self-cured acrylic and bucco - lingually sectioned. They were examined for dye penetration under a stereomicroscope (40 X). For micro leakage analysis at the section level by proportional Odda model, link function and goodness of fit (0.760). Results: There is no significant difference in using the self-etching or total etching systems but significant differences were found in using flow composite and fissure sealant. Micro leakage is less, when fissure sealant is used and compared to flow composite.