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.

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In this work, we fabricated MgO-based magnetic tunnel junction (MTJ) samples to observe behavior of resistance variation, and investigated a stochastic behavior model for MTJ resistance from measured real data. We found the relationship between parallel resistance (R P ), anti-parallel resistance (R AP ), and TMR from the measurements. The variation of barrier thickness affects not only resistance but also TMR. This means that broad R AP distribution is caused by R P distribution. In addition, R AP distribution can be reduced by increasing temperature and bias voltage. We developed a macro model that can evaluate resistance distribution based on the stochastic behavior of MTJ resistance variation from only t ox varied. The amount of resistance variation, which is considered with regard to the circuit performance, can be obtained from Δt ox designed by designer. In addition, the impact for operating circumstance such as bias and temperature can be considered by using fit equations.

We present a bidirectional two-terminal switching device using a Schottky barrier for spin-transfer-torque magnetic random access memory (STT-MRAM), which is composed of a Schottky barrier contact with a metal/semiconductor/metal (M/S/M) structure. The proposed M/S/M switching device provides a bidirectional current flow sufficient to write STT-MRAM using a punch through with an extended depletion region at a junction under a reverse bias of M/S or S/M. In addition, a high on–off ratio of 105 is confirmed under the read condition, which is acceptable for the operation of STT-MRAM. From this work, it is expected that an M/S/M structure with bilateral Schottky junctions will be a promising switch device for STT MRAM beyond 20 nm.

A novel sensing algorithm for non-volatile Spin-Transfer Torque Magneto-resistive Random Access Memory (STT-MRAM) is presented. The dynamic reference sense amplifier (DRSA) improves sensing margin to achieve high reliability and sensitivity by increasing the difference of input voltages of sense amplifier. A dynamic reference sensing algorithm is proposed as a solution for the read margin loss due to variation in magnetic tunneling junction (MTJ) parameters of the STT-MRAM. The proposed sensing method was designed in standard 0.18 um process parameters, and simulation results indicate simultaneously increased the read margin compared with the conventional sensing method.