Atomically Controlled Growth in 2, 1 and OD, and Applications

Abstract

Today’s most advanced semiconductor memory, a 4 Mbit DRAM (Dynamic Random Access Memory) [1] uses about 10¹³ silicon atoms for a 1 bit cell (which includes the silicon in the passive region). As shown in Fig.1, by extrapolating the number with the current slope, 1 Gbit DRAM in 1998 will need 10¹¹–10¹² atoms/bit. It is frequently said that 1 Gbit memory is the last device based on the conventional IC architecture from the viewpoint of microfabrication technology and transistor operation principle. On the other hand, according to the recently proposed concept of molecular devices, molecular memory or sometimes bio-memory, the number of atoms (mainly C, H, O, N) per 1 bit is of the order of 10³ atoms/bit [2]. However, I believe there is no reason to obey the assumption that, at the beginning of the 21st century, we must give up semiconductor research, leaving seven orders of magnitude difference of atoms/bit. 50 or 100-year research with innovated concepts is definitely necessary to reach a 10³ atoms/bit memory, either extrapolating the trend so far or with a somewhat slower trend. It means that the 21st century will still be a semiconductor research age.