5736778 A abstract a high power resistor is formed of a wafer of silicon captured between two molybdenum electrodes a p i n diode of ring shape or wafer shape is concentric with a silicon resistor and has surfaces which are coplanar with the silicon resistor to form a device having an integrated diode and resistor application_number US 75111196 A description referring first to fig1 a conventional monocrystal or polycrystal silicon wafer 10 is grown by conventional techniques and is shaped to desired dimensions as by etching and lapping wafer 10 may have its resistivity controlled by controlled diffusion of phosphorus thereon to have a resistivity ranging from 100 to 10 000 ohm centimeters a thickness ranging from 0 3 to 2 5 millimeters and a diameter if circular of from 15 to 77 millimeters wafer 10 may also have a square elongated rectangular or any other desired topology if desired the silicon wafer can have a variable resistivity across its thickness for example a major portion of its thickness may be of very low resistivity and a small portion of high resistivity the high resistance portion can also be disposed in the center of the wafer thickness the resistivity can also vary in non step fashion over the thickness of the wafer thus the wafer can be thick and strong while still having a high resistance the upper surface of silicon wafer 10 is.