The PN Junction Passivation Process and Performance of Semiconductor Devices

It is shown that a maximum permissible operation temperature of 150 -200 degC for commercial PN junction silicon devices is a limitation determined by insufficiency in the junction passivation process. The passivation process involves suitable treatment and coating of the PN junction peripheral edge with dielectric material layer, so that, a reverse current-voltage characteristic of low leakage current, high voltage and good stability in time to be obtained. PN junction passivation techniques used at this time enable high reverse current level with significant contribution from leakage at the junction edge. The edge current component of reverse current can cause electrical characteristic instability at high junction temperature and for this reason the maximum operation temperature specified in the data sheets is lower than 200 degC. Analysis of electrical characteristics for typical commercial silicon devices indicates significant leakage reverse current flow at the interface between semiconductor and dielectric from the junction periphery. Linear voltage dependence of reverse current for a portion of electrical characteristic is manifestation of junction edge current in the interfacial layer resulted from the passivation process. Further advance in the PN junction passivation technology can lead to operation temperature above 200 degC and higher working voltage for silicon devices.