In a preferred embodiment, a diffused leakage resistor of a high value between approximately 200K ohms and 5M ohm is formed proximate to an MOS power transistor on the same silicon chip. The manufacturer of the chip has the option, using a mask, to connect or not connect the dedicated leakage resistor between the transistor's source and gate during the fabrication of the chip. The resistor is formed using the same masking steps already used to form the MOS transistor. To increase the sheet resistivity (ohms per square) of the resistor, a novel method is used to cause the effective width of the diffused resistor to be substantially narrower than the actual drawn width dimension on the mask. Also using this novel method, the concentration and depth of the dopants forming the resistor diffused region are less than that of the source and drain regions. The resulting resistor will thus have a much higher sheet resistivity than is achieved using conventional methods.