Schottky Diode Series Resistance and Thermal Resistance Extraction From S-Parameter and Temperature Controlled I-V Measurements

A new method for extracting the series resistance and thermal resistance of a Schottky diode is presented. The method avoids the inaccuracies caused by the temperature dependence of the saturation current and ideality factor. These are a major concern for traditional extraction methods, especially when the diode under test has a submicrometer anode diameter and is significantly heated up by the bias current. The method uses theoretical models validated with measurements for the temperature-dependent saturation current and ideality factor, and the series resistance values extracted from low-frequency scattering parameter measurements in the high bias current regime. The main focus of this paper is the accurate extraction of the series resistance. For example, the series resistance value extracted with our method for a discrete diode with a 0.8-mu m anode diameter is 88% larger than the series resistance extracted using traditional techniques. As a by-product from the extraction algorithm, an estimate for the thermal resistance of the diode is obtained. The method is validated with extensive current-voltage (I-V) and scattering parameter measurements of two different commercially available discrete single anode mixer diodes optimized for terahertz operation. I-V measurements are performed at several controlled ambient temperatures and scattering parameter measurements at one known ambient temperature.