Nonvolatile semiconductor memory

Chih-Yuan, L. and Kuan, H. 2009 Nonvolatile semiconductor memory revolutionizing information storage. IEEE Nanotechnol. Mag. 3 4—9. 

Nanocrystals are receiving significant attention for nano-electronics application for the development of future nonvolatile, high density and low power memory devices [1-3]. In nanocrystal complementary metal oxide semiconductor (CMOS) memories, an isolated semiconductor island of nanometer size is coupled to the channel of a MOS field effect transistor (MOSFET) so that the charge trapped in the island modulates the threshold voltage of the transistor (Fig. 1). 

Nonvolatile memory (NVM), silicon-based semiconductors in, 22 257-258 Nonvolatile methylene chloride extract (NVMCE), 23 158... 

J. A. Cooper, Jr., Nonvolatile Random Access Memories in Wide Bandgap Semiconductors... 

CMOS Acronym for Complementary Metal Oxide Semiconductor. An area of nonvolatile memory that contains settings that determine how a computer is... 

Chemical and physical processing techniques for ferroelectric thin films have undergone explosive advancement in the past few years (see Ref. 1, for example). The use of PZT (PbZri- cTi c03) family ferroelectrics in the nonvolatile and dynamic random access memory applications present potentially large markets [2]. Other thin-film devices based on a wide variety of ferroelectrics have also been explored. These include multilayer thin-film capacitors [3], piezoelectric or electroacoustic transducer and piezoelectric actuators [4-6], piezoelectric ultrasonic micromotors [7], high-frequency surface acoustic devices [8,9], pyroelectric intrared (IR) detectors [10-12], ferroelectric/photoconduc-tive displays [13], electrooptic waveguide devices or optical modulators [14], and ferroelectric gate and metal/insulator/semiconductor transistor (MIST) devices [15,16]. 

Nonvolatile ferroelectric random access memory (FRAM) devices Dynamic random access memory (DRAM) and static random access memory (SRAM) devices based on semiconductor technology are volatile that is, they wiU lose stored information when the power fails. Nonvolatile devices such as CMOS (complementary metal oxide semiconductors) and EEPROMs (electrically erasable read-only memories) are forbiddingly expensive for mass-produced electronic devices. As described above (see Section 8.3), the magnitude and direction of polarization of a ferroelectric ceramics can be reversed by applying an external electric field, and this method is used by FRAMs to store (or erase) data. As the materials have a nonlinear hysteresis curve, the polarization remains in the same state when the voltage is switched off (i.e., the information originally stored is maintained). In addition, FRAMs may be radiation-hardened for use in harsh environments such as outer space (Scott and Paz de Araujo, 1989). 

M Kanoun, A. Souifi, T. Baron, and F. Mazen, Electrical study of Ge-nanocrystal-based metal-oxide-semiconductor structures for p-type nonvolatile memory applications, Appl. Phys. Lett., 84, 5079-5082... 

Another technique whereby the two possible electrical polarization states can be recorded as well as read by means of a transistor was described recently (145). A nonvolatile 64K ferroelectric random-access memory (RAM) based on PZT as ferroelectric storage medium in combination with the common semiconductor dreuils was developed... 

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