Toshiba says it has developed a mosfet based on spin transport electronics, or spintronics.
Spintronics is a semiconductor technology that makes use of the spin and magnetic moment inherent in electrons. Toshiba claimed this is the first time a spintronics mosfet cell has been fabricated and verified as stable.
Full details of the cell and its technologies are being presented at the International Electronics Devices meeting in the US.
Toshiba is carrying out the research because it believes that mosfet devices based on current semiconductor miniaturisation technologies will inevitably hit a wall as they meet such problems as relative degraded performance due to the increase in the resistance of global wiring and increased power consumption due to current leakage.
"Spintronics is regarded as a major candidate among potential solutions to this problem, but its application in a transistor has only recently started and has only been partially proved," said the company.
Electrons in a magnetic layer naturally are spin polarized in one of two spin states, spin up or spin down, and the majority state determines the spin state. These spin states are more or less permanent in a magnetic layer, realizing a nonvolatile characteristic that can be used to store data.
Spin current can be flowed into the same spin state in a magnetic layer, and this capability changes the impedance characteristics, which determine the read signal of a spin device.
Toshiba has introduced magnetic layers into the source and drain of a mosfet cell, and successfully applied these to controlling spin direction by the spin-transfer-torque-switching (STS) method, and by applying gate and source/drain voltages.
A magnetic tunnel junction3 is applied for write operation of STS in the magnetic layers, which are formed with full-Heusler alloy, an intermetallic that acts as a high spin polarizer.
The technology is expected to be used in commercial devices after 2015.