are shown and described simply by way of illustration of the best mode contemplated the disclosure is capable of other and different embodiments and its several details are capable of modifications in various obvious respects accordingly the drawings and description are to be regarded as illustrative in nature and not as restrictive adverting to fig1 illustrates in cross section an example of si wafer 101 having a smooth upper surface 103 the si wafer can have a variety of diameters from 25 4 mm to 450 mm and can be formed of a crystalline si the si wafer serves as a substrate for microelectronic devices built in and over the wafer and undergoes many microfabrication process steps such as doping or ion implantation etching deposition of various materials and photolithographic patterning adverting to fig2 a the si wafer 101 is textured to form a plurality of pyramid shapes 201 on the upper surface 103 of the si wafer the pyramid shapes 201 have a peak 203 and a trench 205 the height of each pyramid shape 201 from its peak 203 to the bottom of trench 205 is between 100 nm to 200 nm the textured surface of the si wafer 101 is formed on one side of the si wafer 101 by etching processes including dry or wet etching processes or a combination of wet dry process to form the pyramid shapes 201 a dry etch process such as a sulfur hexafluoride based dry etch can be used to produce the irregularities on the surface of the si wafer 101 the entire upper surface of si wafer 101 can be etched.