MOS DRAMs Replace Magnetic Core Arrays

By the early 1970s, dynamic circuit designs, coupled with the silicon gate MOS (Metal-Oxide-Silicon) process, made DRAM chips competitive in cost with magnetic cores.

Introduced at 1¢ per bit, Intel’s 1024-bit 1103 DRAM opened the market for semiconductor main memory. In 1972, IBM pioneered a fast N-channel MOS process for its System 370 Model 158 and quickly became the world’s largest semiconductor memory manufacturer.

For the next 30 years, advances in technology—coupled with aggressive international competition—increased density by a factor of four approximately every three years. A 4K-bit device arrived in 1973, the 16K in 1976 and the 64K in 1979. The first gigabit (1,000 million bits) DRAM arrived in 2000. Every increase in density brought a corresponding decrease in cost that opened up new applications in PCs, games, and portable electronic products.