Embedded memory evolves

摘要

IN THE SEARCH FOR ON-CHIP RAM, SOI TECHNOLOGY OFFERS A MEW ANSWER. Ever since its invention in the 1970s, DRAM (dynamic RAM) has been the most popular form of semiconductor memory. Indeed, modern computing and communication systems could not exist without DRAM. The first volume-production device had a capacity of only 4 kbits, but, within 30 years, the capacity has increased a millionfold. At about the same time that DRAM emerged, the microprocessor appeared, evolving from early calculator chips. This development quickly led to the development of the PC. When people started trying to use these new marvels, two limitations became apparent: The processor chip needed to be faster, and more memory was necessary. The same pressure for processor speed and memory size came from the communications sector, with the result that logic and memory have followed two divergent evolutionary paths.