Development of Nonvolatile FET Memory with Helical Polymer

以多肽和DNA为记忆材料，制备了具有螺旋二级结构的记忆器件。以多肽为例，通过优化分子间相互作用可以增加螺旋三级结构。当螺旋三级结构大量加入薄膜时，存储器在较低的电场下表现出驱动特性。由于分子取向工艺可以增加结构，因此用该工艺制备的厚膜（4μm）器件与用其他工艺制备的薄膜（700nm）器件在相同的电压下驱动。结果表明，由于针孔的减少，器件的成品率由原来的50% ~ 70%提高到100%。以DNA为例，将DNA与表面活性剂络合以去除离子。在dna -表面活性剂复合物制备的OTFT中，由于关闭电流的减小，获得了较高的开/关比。此外，当PMMA在dna -表面活性剂层上分层时，并五苯作为半导体层沉积在PMMA表面，显示出大晶粒和高结晶度。结果表明，通过提高导通电流，在10V下实现了104的通断比和1000小时的保持时间。

Memory devices were fabricated with polypeptide and DNA as a memory material which have helical secondary structure. In the case of polypeptide, it was revealed that the helical tertiary structure can be increased by optimizing the intermolecular interaction. When the helical tertiary structure was much incorporated into the film, the memory device showed driving at lower electric field than that in the absence of the structure. Since the structure can be increased by molecular alignment processes, the device fabricated with thick film (4μm) by the process was driven at same voltage to that of thin film (700nm) prepared by other process. As the results, the yield rate of the device was improved from 50～70 % to 100% due to decrease in pinhole. In the case of DNA, complexing DNA with surfactant was carried out in order to remove the ion. In the OTFT fabricated with DNA-surfactant complex, high on/off ratio was obtained because of decrease in the off-current. Further, when PMMA was layered on the DNA-surfactant layer, pentacene deposited on the PMMA surface as a semiconductor layer showed large grain and high crystallinity. As the results, 104 of on/off ratio at 10V and 1000 hours of the retention time were achieved due to improve the on-current.