Elimination of Enhanced Low-Dose-Rate Sensitivity in Linear Bipolar Devices Using Silicon-Carbide Passivation

The type of final chip passivation layer used to fabricate bipolar linear circuits can have a major impact on the total dose hardness of circuits. It is demonstrated that National Semiconductor Corporation bipolar linear devices fabricated with only an amorphous silicon carbide passivation layer do not exhibit enhanced low-dose-rate sensitivity (ELDRS), while devices from the same production lot fabricated with other types of passivation layers are ELDRS sensitive. SiC passivation possesses mechanical, electrical and chemical properties that make it compatible with linear device fabrication processes. These properties of SiC passivation layers, combined with the excellent radiation response of devices passivated with SiC, make SiC passivation layers a very attractive choice for devices packaged in either ceramic or plastic-encapsulated packages for use in space environments.