摘要:
There is provided a magnetic memory with using a magnetoresistive effect element of a spin-injection magnetization reversal type, in which a multi-value operation is possible and whose manufacturing and operation are simple. A preferred aim of this is solved by providing two or more magnetoresistive effect elements which are electrically connected in series to each other and by selecting one of the series-connected elements depending on a direction of a current carried in the series-connected elements, a magnitude thereof, and an order of the current thereof for performing the writing operation. For example, it is solved by differentiating plane area sizes of the respective magnetoresistive effect elements which have the same film structure from each other so as to differentiate resistance change amounts caused by respective magnetization reversal and threshold current values required for respective magnetization reversal from each other.
摘要:
There is provided a magnetic memory with using a magnetoresistive effect element of a spin-injection magnetization reversal type, in which a multi-value operation is possible and whose manufacturing and operation are simple. A preferred aim of this is solved by providing two or more magnetoresistive effect elements which are electrically connected in series to each other and by selecting one of the series-connected elements depending on a direction of a current carried in the series-connected elements, a magnitude thereof, and an order of the current thereof for performing the writing operation. For example, it is solved by differentiating plane area sizes of the respective magnetoresistive effect elements which have the same film structure from each other so as to differentiate resistance change amounts caused by respective magnetization reversal and threshold current values required for respective magnetization reversal from each other.
摘要:
In MRAM using a spin-transfer torque switching, a sufficient writing operation with a small memory cell is realized, and a reading current is enlarged while a reading disturbance is suppressed. In the case where the free layer of the tunnel magneto-resistance element is located on the side of the bit line, using a PMOS transistor, and in the case where the fixed layer of the tunnel magneto-resistance element is located on the side of the bit line, using an NMOS transistor, an anti-parallel writing in a source grounding operation is performed. The reading and writing operation margin is improved by performing a reading operation in an anti-parallel writing direction.
摘要:
In a memory using spin transfer torque, state of the spin is made unstable by applying a weak pulse before rewriting to reduce rewrite current. Reading of high-speed operation is performed with current in a regime where the current becomes non-linearly increases corresponding to the pulse width to suppress disturb. Further, fluctuation of respective memory cells is suppressed by a driving method setting the amount of spin constant by bit line charge to suppress read disturb.
摘要:
A magnetic memory device comprises a magnetic tunnel junction (MTJ) having a ferromagnetic free layer, and exhibits a first, relatively high resistance state, and a second, relatively low resistance state. To write to the magnetic memory device a current IMTJ is driven through the MTJ. For a first duration, the current is equal to a DC threshold current, being the DC current required to switch the multilayer structure between the first state and the second state. This induces a C-like domain structure in the free layer. For a second duration, the current IMTJ is larger than the DC threshold current. This causes the MTJ to switch states. The current requited to cause switching is less than that required using a uniform current pulse.
摘要:
To write information on a memory cell of SPRAM formed of an MOS transistor and a tunnel magnetoresistive element, the memory cell is supplied with a current in a direction opposite to a direction of a current required for writing the information on the memory cell, and then, the memory cell is supplied with a current required for writing. In this manner, even when the same information is sequentially written on the memory cell, since the currents in the two directions are caused to flow in pairs in the tunnel magnetoresistive element of the memory cell each time information is rewritten, deterioration of a film that forms the tunnel magnetoresistive element can be suppressed. Therefore, reliability of the SPRAM can be improved.
摘要:
To write information on a memory cell of SPRAM formed of an MOS transistor and a tunnel magnetoresistive element, the memory cell is supplied with a current in a direction opposite to a direction of a current required for writing the information on the memory cell, and then, the memory cell is supplied with a current required for writing. In this manner, even when the same information is sequentially written on the memory cell, since the currents in the two directions are caused to flow in pairs in the tunnel magnetoresistive element of the memory cell each time information is rewritten, deterioration of a film that forms the tunnel magnetoresistive element can be suppressed. Therefore, reliability of the SPRAM can be improved.
摘要:
A magnetic memory device comprises a magnetic tunnel junction (MTJ) connecting to a bit line to a sense line through an isolation transistor. The MTJ includes a ferromagnetic layer having a magnetic hard axis. An assist current line overlies the bit line and is insulated from the bit line. The MTJ is switchable between a first, relatively high resistance state and a second, relatively low resistance state. The assist current line applies a magnetic field along the magnetic hard axis in the ferromagnetic layer, independently of current flow through the MTJ for assisting switching of the MTJ between the first and second states.
摘要:
In a memory using spin transfer torque, state of the spin is made unstable by applying a weak pulse before rewriting to reduce rewrite current. Reading of high-speed operation is performed with current in a regime where the current becomes non-linearly increases corresponding to the pulse width to suppress disturb. Further, fluctuation of respective memory cells is suppressed by a driving method setting the amount of spin constant by bit line charge to suppress read disturb.
摘要:
In MRAM using a spin-transfer torque switching, a sufficient writing operation with a small memory cell is realized, and a reading current is enlarged while a reading disturbance is suppressed. In the case where the free layer of the tunnel magneto-resistance element is located on the side of the bit line, using a PMOS transistor, and in the case where the fixed layer of the tunnel magneto-resistance element is located on the side of the bit line, using an NMOS transistor, an anti-parallel writing in a source grounding operation is performed. The reading and writing operation margin is improved by performing a reading operation in an anti-parallel writing direction.