Characterization of dielectric charging in RF MEMS capacitive switches

RF MEMS capacitive switches show great promise for use in wireless communication devices such as mobile phones, but the successful application of these switches is hindered by reliability concerns: charge injection in the dielectric layer (SiN) can cause irreversible stiction of the moving part of the switch. We present a new way to characterize charge injection. By stressing the dielectric with electric fields on the order of 1 MV/cm, we inject charge in the dielectric, and use a new method to measure the effects it has on the C-V curve. Instead of measuring the change in the pull-in voltage, this method measures the change in the voltage at which the capacitance is minimal. This way, no extra charge is injected during the measurement of the amount of injected charge, which reduces the effect it has on the tested switches, so that the effect of the intentionally induced stress voltage is not obscured by the measurement method

Fast RF-CV characterization through high-speed 1-port S-parameter measurements

We present a novel method to measure the capacitance-voltage relation of an electronic device. The approach is accurate, very fast, and cost-effective compared to the existing off-the-shelf solutions. Capacitances are determined using a single-frequency 1-port S-parameter setup constructed from discrete components. We introduce a new way to correct for non-linearities of the used components, which greatly increases the accuracy with which the phase and magnitude of the reflected signal is measured. The measurement technique is validated on an RF-MEMS capacitive switch and a BST tunable capacitor. Complete capacitance-voltage curves are measured in less than a millisecond, with a measurement accuracy well below 1%.\ud \u

Atom lithography of Fe

Direct write atom lithography is a technique in which nearly resonant light is used to pattern an atom beam. Nanostructures are formed when the patterned beam falls onto a substrate. We have applied this lithography scheme to a ferromagnetic element, using a 372 nm laser light standing wave to pattern a beam of iron atoms. In this proof-of-principle experiment, we have deposited a grid of 50-nm-wide lines 186 nm apart. These ultraregular, large-scale, ferromagnetic wire arrays may generate exciting new developments in the fields of spintronics and nanomagnetics. (C) 2004 American Institute of Physics

Center-Shift Method for the Characterization of Dielectric Charging in RF MEMS Capacitive Switches

Radio frequency (RF) micro-electro-mechanical systems (MEMS) capacitive switches show great promise for use in wireless communication devices such as mobile phones, but for the successful application of these switches their reliability needs to be demonstrated. One of the main factors that limits the reliability is charge injection in the dielectric layer (SiN) which can cause irreversible stiction of the moving part of the switch. We present a way to characterize charge injection. By stressing the dielectric with electric fields on the order of 1 MV/cm, we inject charge in the dielectric and measure the effects it has on the curve. Instead of conventionally measuring the change of the pull-in voltage, the presented center shift method measures the change of the voltage at which the capacitance is minimal. This way, the measurement method does not influence the charge injected by the stress voltage. Another advantage is that the measurement of the amount of injected charge is not influenced by changes in the width of the curve. These two advantages make it possible to test RF-MEMS capacitive switches in a more accurate way

Characterization of dielectric charging in RF MEMS

Capacitive RF MEMS switches show great promise for use in wireless communication devices such as mobile phones, but the successful application of these switches is hindered by the reliability of the devices: charge injection in the dielectric layer (SiN) can cause irreversible stiction of the moving part of the switch. Our research comprises a study on charge injection by stressing the dielectric with electric fields on the order of 1 MV/cm, and by measuring the effects it has on the C-V curve

Kelvin probe study of laterally inhomogeneous dielectric charging and charge diffusion in RF MEMS capacitive switches

In this paper we use Scanning Kelvin Probe Microscopy (SKPM) to detect charge in the dielectric of RF MEMS capacitive switches. We observe a laterally inhomogeneous distribution. Laterally inhomogeneous dielectric charging leads to a narrowing of the C-V curve [1], and can lead to stiction of the membrane. The measurements show that trapped charges slowly diffuse, which reduces the inhomogeneity and shows that charge is vertically confined. From these measurements we estimate the lateral diffusion coefficient of trapped charges

Demonstration of Parallel Scanning Probe Microscope for high throughput metrology and inspection

With the device dimensions moving towards the 1X node and below, the semiconductor industry is rapidly approaching the point where existing metrology, inspection and review tools face huge challenges in terms of resolution, the ability to resolve 3D and the throughput. Due to the advantages of sub-nanometer resolution and the ability of true 3D scanning, scanning probe microscope (SPM) and specifically atomic force microscope (AFM) are considered as alternative technologies for CD-metrology, defect inspection and review of 1X node and below. In order to meet the increasing demand for resolution and throughput of CD-metrology, defect inspection and review, TNO has previously introduced the parallel SPM concept, consisting of parallel operation of many miniaturized SPMs on a 300 and 450 mm wafer. In this paper we will present the proof of principle of the parallelization for metrology and inspection. To give an indication of the system’s specifications, the throughput of scanning is 4500 sites per hour, each within an area of 1 μm2 and 1024 ×1024 pixels