SBIR-STTR Award

The purpose of this Phase I SBIR project is to reduce the power and increase the speed of reprogrammable non-volatile chalcogenide devices. The proposed method employs a porous monolayer of carbon nanotubes (CNTs) as local heating elements for chalcogenide devices. By exploiting the molecular nature of carbon nanotubes, very large local temperature changes can be induced on timescales much shorter than using traditional thin film resistors. This innovation directly addresses the bottleneck in performance stemming from the relatively long delay associated with the crystallizing transition of Ge2Sb2Te5 layers. Also, due to the increased heating efficiency of CNT fabrics, a lower total overall power is required to effect each state transition. The proposed Phase I project focuses on electrical and thermal measurements of patterned CNT fabrics and patterned CNT/Ge2Sb2Te5 bi-layers. Completion of a successful Phase I program will allow CNT/Ge2Sb2Te5 test devices to be designed in Phase II and incorporated into BAE's current CRAM technology, increasing the speed and decreasing the power of the integrated chalcogenide devices, which forms a critical component in the effort to exploit higher performance, reprogrammable, reliable and "agile" radiation tolerant non-volatile memory systems for space

There exists a great need for a non-volatile radiation-hardened, high density random access memory with performance comparable to that of a commercial dynamic random access memory (DRAM) and with the non-volatility of an electrically erasable programmable read-only memory (EEPROM) for space based applications. Current possible solutions for filling the void of radiation hard non-volatile memories are FeRAM, MRAM, NRAM, and CRAM. From these options, CRAM is a major prospect to be incorporated in current space computer architectures for the hostile radiation environment of space. CRAM, however, still requires some advancement/refinement in technology to be a suitable replacement for Flash memory with operating characteristics similar to SRAM. Several issues associated with CRAM technology are the long SET and RESET times and the high powers required to change the phase of the memory element. Nantero’s carbon nanotube (CNT) nanoelectronic technology may assist in overcoming several of the hurdles that are hampering the incorporation of CRAM as a reliable radiation hard non-volatile memory. The goal of this Phase II proposal is to investigate the utilization of CNT nanoheaters to change the phase of the chalcogenide material employed in BAE’s CRAM technology, creating a prototype CNT heated CRAM element

Keywords:
carbon nanotubes, CNTs, chalcogenide, CRAM, radiation hardened, memory, nanoheaters, NVRAM