Method for Growing Very Thick Thermal Local Silicon Oxide Structures and Silicon Oxide embedded Spiral Inductors

A method is provided for fabricating thick silicon oxide structures, such as an embedded inductor. A Deep Reactive Ion Etch (DREI) etches the top silicon layer of a substrate to form high aspect ratio Si features, called trench texturing. The Si features are oxidized to form silicon oxide features. Adjacent Si features are separated by a trench width (S(0)), so that after oxidation, adjacent Si oxide features are formed separated by trench width (S(t)), where S(t)≤S(0) (e.g., S(t)=0). If the Si features have a width WSi(0)>1.2728 S(0), then the adjacent silicon oxide features form an amorphously merged silicon oxide feature with a planar top surface. The silicon oxide features have a height (HOX(t)) responsive to the trench width (S(0)), the Si feature width (WSi(t)), and the Si feature aspect ratio. After oxidation, inductor metal is deposited in trenches where WSi(0)