Trends in semiconductor memories

An overview is given of the state-of-the-art of the different semiconductor memory types and the trends in their future developments are discussed. The paper treats the physical operation principles, the evolution in technology and device concepts and the new developments and trends for each class of memory devices comprising SRAM (static random-access memories), DRAM (dynamic random-access memories), EPROM (erasable programmable read-only memories) and full-feature and flash EEPROM (electrically erasable programmable read-only memories). The reliability problems specific to the above mentioned memory types are also discussed. Finally the different approaches and technologies are compared in terms of their density, speed performance, applications, market and long term trends.