A three dimensional shallow trench isolation structure including sets of parallel trenches extending in two perpendicular directions may be formed by depositing a conformal deposition in a first set of parallel trenches, oxidizing the second set of trenches to enable selective deposition in said second set of trenches and then conformally depositing in said second set of trenches. The seal can be hermetic or non-hermetic. The method has the additional benefits that it simultaneously reduces the pH of the water as well as reducing the concentration of bicarbonate ions. The apparatus and methods of the present invention introduce a known and variable phase offset during the signal averaging process between the signal waveform being measured and the internally generated coherent noise, thereby allowing such coherent noise to be averaged, and therefore reduced, during the signal averaging process. The portable terminal can store images and voices of both users during video communication by successively storing video and audio data, which are transmitted or received, in response to a user’s key input and merging the video and audio data into a single file. The resulting imaging member is resistant to chemical contaminants, photoelectrically stable, fatigue cracking suppression, and has a simplified material structure which is curl-free without the need of an anticurl back coating layer.