Dynamic RAM

3

DRAM Technologies

3.1    Introduction

DRAM is a volatile memory since information stored is destroyed once the power supply to it stops even for a short duration. Information is also lost because of charge leakage from the storage capacitor unless it is periodically charged or refreshed. In spite of this complexity of operation and comparatively larger data access time with respect to SRAM, DRAMs have been produced in largest quantities because of their low cost per bit [1]. There are quite a few reasons for the low cost of DRAM memory. Prominent among the reasons is the changeover from 6/4 transistor SRAM to 3 transistor DRAM and eventually to single-transistor–single-capacitor DRAM. Consumed chip area per bit further continued to reduce ...