Bidirectional Two-Terminal Switching Device for Non-Volatile Random Access Memory

Abstract

Weighing at low gas pressures is a technique which is highly susceptible to temperature inhomogeneities. These temperature inhomogeneities cause spurious mass changes, the effect being usually called the thermomolecular flow effect. In a former paper by Poulis, Pelupessy, Massen and Thomas these effects were explained in the low pressure region (below 10 mtorr) on the basis of transverse and longitudinal Knudsen forces, which are both related to the Knudsen pressure difference, which at low pressures accompanies a temperature inhomogeneity. Though in nature a low pressure effect, the thermomolecular flow effect appears to be present at pressures as high as 100 torr. In the present paper the theory, originally set up for the low pressure region, is extended to higher pressures. Here, laminar gas flow can arise, accompanied by shearing forces, which have been allowed for in the theory. The theoretical results are compared with experimental data.

Bidirectional Two-Terminal Switching Device with Metal–Semiconductor–Semiconductor Structures for 4F2 Spin-Transfer-Torque Magnetoresistance Random Access Memory Cell

“…In our previous works, we proposed N+/P/N+ and Schottky junction switching devices with two terminals as one of the candidate devices. [13][14][15] However, they still have some problems in that it is difficult to ensure junction quality and stable fabrication. Here, the M/S/S structure was practically investigated to improve the process feasibility as well as the switching characteristics.…”

Bidirectional Two-Terminal Switching Device Using Schottky Barrier for Spin-Transfer-Torque Magnetic Random Access Memory

“…However, several critical issues such as an insufficient write current and a junction control of the P layer are sources of concern. 11,12) Here, the M/S/M structure is investigated to solve this problem. In addition, since a seed layer material such as tantalum (Ta), which is based on a perpendicular magnetic anisotropy (PMA) MTJ, can be easily made into an M/S Schottky barrier contact, the device fabrication process will be simple and more feasible than those in refs.…”

“…8) The M/S/M structure provides a lower serial resistance to metal materials from the replacement of the outer two terminals composed of poly-Si, and better controllability of P junction length from the lack of additional N þ doping compared with the N þ /P/N þ poly-Si device that we proposed previously. 11,12)…”

“…[7][8][9][10] In our previous work, we proposed a bilateral polycrystalline silicon (poly-Si) junction with an N þ /P/N þ structure as a two-terminal switching device for the crossbar array architecture of STT-MRAM. 11,12) In this work, a twoterminal switching device with Schottky junctions is newly proposed. A junction device is composed of metal/semiconductor/metal (M/S/M) with a Schottky contact at the interfaces of M/S and S/M.…”