Method and Apparatus for Non-Contact Measurement of Forward Voltage, Saturation Current Density, Ideality Factor and I-V Curves in P-N Junctions

摘要

Non-contact measurement of one or more electrical response characteristics of a p-n junction includes illuminating a surface of the p-n junction with light of a first intensity having a modulation or pulsed characteristic sufficient to establish a steady-state condition in a junction photovoltage (JPV) of the p-n junction, measuring a first JPV from the p-n junction within the illumination area, illuminating the surface of the p-n junction with light of an additional intensity, measuring an additional photovoltage from the portion of the p-n junction within the illumination area, determining a photocurrent density of the p-n junction at the first intensity. The non-contact measurement further includes determining the forward voltage, the saturation current density, the ideality factor or one or more I-V curves with the measured first photovoltage, the measured additional photovoltage and/or the determined photocurrent density of the p-n junction.

主权项

1. An apparatus for contactless measurement of one or more characteristics of a p-n junction comprising:
an illumination unit for illuminating a surface of a p-n junction with light at one or more selected intensities and one or more selected frequencies; a measurement unit including at least a first measurement element including a first transparent electrode positioned proximate to the p-n junction and configured to transmit light from the illumination unit to the surface of the p-n junction, wherein the first transparent electrode has a first area for measuring a junction photovoltage of the p-n junction corresponding with the first area within the illuminated area, wherein the first area of the first electrode is smaller than the area illuminated by the illumination sub-system in order to limit an effect of lateral spreading of the junction photovoltage on the measurement of the junction photovoltage; and a controller communicatively coupled to at least the measurement unit and the illumination unit, the controller configured to: control at least one of light intensity or frequency of the light from the illumination unit; receive one or more measurements of the junction photovoltage from the measurement unit at the one or more selected light intensities and one or more selected frequencies; and determine at least one of a photocurrent density of the p-n junction, a forward voltage of the p-n junction, a saturation current density of the p-n junction, an ideality factor of the p-n junction or one or more I-V curves of the p-n junction with the one or more measurements of the junction photovoltage received from the measurement unit.