The water content of phosphoric acid in etching silicon nitride and silicon dioxide plays an important role. An increase in water content increases the etch rate of silicon nitride and decreases the etch rate of silicon dioxide. The highest possible temperature for a fixed water content at atmospheric pressure in the system H2O-P2O5 is realized by boiling the liquid and refluxing the vapor phas...

Monte Carlo simulations of pattern-dependent charging during oxide etching predict that the etch rate scaling with aspect ratio breaks down when surface discharge currents are significant. Under conditions of ion-limited etching and no inhibitor deposition, the etch depth depends on the maximum incident ion energy, reaction threshold, and surface discharge threshold, and is the same irrespectiv...

The mechanisms underlying selective etching of a SiO2 layer over a Si or Si3N4 underlayer, a process of vital importance to modern integrated circuit fabrication technology, has been studied. Selective etching of SiO2-to-Si3N4 in various inductively coupled fluorocarbon plasmas (CHF3 , C2F6/C3F6 , and C3F6/H2) was performed, and the results compared to selective SiO2-to-Si etching. A fluorocarb...

We report the effect of N2 addition to C4F8 and C4F8 /Ar discharges on plasma etching rates of organosilicate glass ~OSG! and etch stop layer materials (Si3N4 and SiC!, and the results of surface chemistry studies performed in parallel. N2 addition exhibits different effects in C4F8 and C4F8 /Ar plasmas, which may be explained by a higher plasma density, electron temperature, and possibly, the ...

background and aims. the aim of this study was to evaluate the effect of different etching times on enamel color stability after immediate versus delayed exposure to colored artificial saliva (cas). materials and methods. human first premolars were divided into five groups of twenty. a colorimeter was used according to the cie system on the mid-buccal and mid-lingual surfaces to evaluate initia...

The purpose of this study was to characterize the etching mechanism, namely, the etching rate and the activation energy, of a titanium dental implant in concentrated acid and to construct the relation between the activation energy and the nanoscale surface topographies. A commercially-pure titanium (CP Ti) and Ti-6Al-4V ELI surface were tested by shot blasting (pressure, grain size, blasting di...

A new model is proposed that explains the anisotropy of the etch rate of single crystalline silicon in certain etchants. It is inspired from theories of crystal growth. We assume that the ( l l l ) face is flat on an atomic scale. Then the etch rate should be governed by a nucleation barrier of one atomic layer deep cavities. The origin of the nucleation barrier is that the formation of a too s...