IMPACT OF INTERFACE OXIDE TYPE ON THE GAMMA RADIATION RESPONSE OF SIC TTL ICS

Abstract

In this study, we investigate the impact of Gamma Radiation on 4H Silicon Carbide (SiC) Transistor-Transistor Logic (TTL) integrated circuits (ICs), particularly focusing on inverters processed with distinct types of interface oxides: Thermally Grown, Chemical Vapor Deposition, and Atomic Layer Deposition. This research was conducted using a ⁶⁰Co source at Hiroshima University, applying varied radiation doses (17.9 rad_(Si)/s, 7.3 rad_(Si)/s, and 2.47 rad_(Si)/s) to assess the resilience of the SiC inverters under these conditions. Our findings reveal that thermal oxides (Batch 1: W₁ and W₂) demonstrate higher radiation resilience compared to ALD and CVD interface oxides (Batch 2: W₃ and W₄), attributable to their denser structure and fewer defects. The study also identifies that while the inverters exhibit marginal degradation at gamma doses nearing 700 krad (under 6%), the most critical operational state is the passive mode (V_CC = V_IN = 0 V), where the build-up of induced charge in the oxide and interface may lead to early IC degradation of the noise margins. The outcomes from this research provide insights into the processing flow and enhancement of SiC electronics. Our results underscore the potential of SiC-based ICs in environments with high radiation levels, such as space missions, nuclear reactors, and medical applications, due to their enhanced radiation tolerance.