For more than a decade, DRAM has been serving as the technology driver of semiconductor industry and, for the time being, it seems to play the similar role past the year 2000. This can be typically exemplified by lithography evolution which has evolved from g-line(=438nm) stepper to Deep UV(KrF,=248nm) scanners. In a year or two, new sources will emerge as potential tools of lithography such as KrF(=193nm), electron beam or x-ray. The same is true of materials related to the evolution of DRAM technologies. These innovations of technologies and materials all result from scale-down of elemental devices in memory chip which crucially affects the cost of manufacturing. Therefore, evolution of future DRAMs muse satisfy economics of manufacturing as well as requirements of scaling of devices in terms of both dimensional and electrical characteristics. In this paper, evolution of DRAM technologies will be discussed from those view-points.
