REALIZATION OF A HUGE-SCALE RADIATION-HARDENED OPTICALLY RECONFIGURABLE GATE ARRAY VLSI

抄録

In our laboratory, we have been developing a radiation- hardened optically reconfigurable gate arrays (RHORGAs) with 1 Grad total-ionizing-dose tolerance [1]-[5]. The RHORGAs is about 1000 times higher total-ionizing-dose tolerance than current available radiation-hardened VLSIs. For example, in order to implement an AI system for autonomous decommissioning robots, a large-size RHORGA-VLSI is required. However, in this case, the yield ratio of RHORGA-VLSIs is main concern. Since the huge-scale RHORGA-VLSIs fabricated by using a latest process technology might have many defects points. However, the RHORGA-VLSIs can accept production failures in addition to permanent failures caused by total-ionizing-dose effect. A RHORGA consists of a programmable gate array VLSI, a holographic memory, and a laser array. In current field programmable gate arrays (FPGAs), the gate array is configured electrically in a serial connection. On the other hand, the RHORGAs can be reconfigured optically in parallel using a holographic memory and a laser array. Parallel configuration is robust for any defect mode while serial configuration is weak for defects. Therefore, the RHORGAs is more robust than current available radiation-hardened VLSIs. In this paper, we have designed a new RHORGA-VLSI with four clock distributions and have implemented four 16-bit adder circuits onto the RHORGA-VLSI with defect areas. The 16-bit adder circuits could work correctly on the RHORGA-VLSI. In the RHORGA, even if three clock distribution are down, the rest clock signal can correctly keep any operation. Therefore, the RHORGA is strong for both of total-ionizing-dose effect and production failure.