Neocera LLC

Bryans Road, MD, United States

Neocera LLC

Bryans Road, MD, United States

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Bachi N.,National University of Tucuman | Bridoux G.,National University of Tucuman | Villafuerte M.,National University of Tucuman | Ferreyra J.M.,National University of Tucuman | And 3 more authors.
Applied Physics Letters | Year: 2017

We report a study of the photoconducting properties of semiconducting SrTiO3 thin films. The photoconducting spectrum shows a pronounced rise around 3.2 eV with a typical indirect gap dependence, involving a transversal optical phonon of 25 meV. While these features remain unaltered under the influence of an applied electric field in ambient conditions, in a vacuum the rest of the spectrum does not, shifting to lower energies for higher electric fields. Time dependent photoconductivity response while illumination is applied confirms the loss of efficiency of the 3.7 eV transition. At low-temperatures, the photoconducting spectrum at low-electric fields has striking similarities to the ones at room-temperature for high-electric fields. This ability to control the photoconducting response through external parameters is explained considering a model of a downward band bending generated by oxygen vacancies at the surface in concomitant with recent findings at the surface of SrTiO3. © 2017 Author(s).


Gaudestad J.,Neocera LLC | Talanov V.,Neocera LLC | Huang P.C.,TSMC
Microelectronics Reliability | Year: 2012

Space Domain Reflectometry is a newly developed non-destructive failure analysis technique for localizing open defects by imaging the magnetic field generated by a radio frequency (RF) current induced in the sample. The technique was used to locate a cracked microbump in a daisy chain between two full 725-μm-thick dies. © 2012 Elsevier Ltd. All rights reserved.


Vallett D.,PeakSource Analytical LLC | Gaudestad J.,Neocera LLC | Richardson C.,Allied High Technology Products Inc.
Conference Proceedings from the International Symposium for Testing and Failure Analysis | Year: 2014

Magnetic current imaging (MCI) using superconducting quantum interference device (SQUID) and giant-magneto-resistive (GMR) sensors is an effective method for localizing defects and current paths [1]. The spatial resolution (and sensitivity) of MCI is improved significantly when the sensor is as close as possible to the current paths and associated magnetic fields of interest. This is accomplished in part by nondestructive removal of any intervening passive layers (e.g. silicon) in the sample. This paper will present a die backside contour-milling process resulting in an edge-to-edge remaining silicon thickness (RST) of < 5 microns, followed by a backside GMR-based MCI measurement performed directly on the ultra-thin silicon surface. The dramatic improvement in resolving current paths in an ESD protect circuit is shown as is nanometer scale resolution of a current density peak due to a power supply short-circuit defect at the edge of a flip-chip packaged die. Copyright © 2014 ASM International® All rights reserved.


Talanov V.V.,Semilab United States LLC | Talanov V.V.,Neocera LLC | Barga C.D.,New Mexico Institute of Mining and Technology | Wickey L.,New Mexico Institute of Mining and Technology | And 5 more authors.
ACS Nano | Year: 2010

Near-field scanning microwave microscopy is employed for quantitative imaging at 4 GHz of the local impedance for monolayer and few-layer graphene. The microwave response of graphene is found to be thickness dependent and determined by the local sheet resistance of the graphene flake. Calibration of the measurement system and knowledge of the probe geometry allows evaluation of the AC impedance for monolayer and few-layer graphene, which is found to be predominantly active. The use of localized evanescent electromagnetic field in our experiment provides a promising tool for investigations of plasma waves in graphene with wave numbers determined by the spatial spectrum of the near-field. By using near-field microwave microscopy one can perform simultaneous imaging of location, geometry, thickness, and distribution of electrical properties of graphene without a need for device fabrication. © 2010 American Chemical Society.


Gaudestad J.,Neocera LLC | Talanov V.V.,Neocera LLC | Huang P.C.,TSMC
Electronic Device Failure Analysis | Year: 2012

Magnetic current imaging (MCI) is found to image open defects in a fully assembled double-stacked dice inside a mold compound package with ball grid array (BGA) by increasing the bandwidth of the SQUID electronics up to 200 MHz. By imaging the magnetic field of a standing wave in the vicinity of the open, the RF MCI microscope Magma recovers the standing wave current profile and locates the open. In a continuity analysis, a BGA sample containing double-stacked dice revealed that High 1 (H1) was open to Ground 1 (G1) and Ground 2 (G2), showing infinite resistance when this connection pair should have shown 400 kω. Comparison of the physical failure analysis (FA) result confirms that space domain reflectometry (SDR) found the defect accurately. The crack are caused by the through-silicon vias (TSV) manufacturing process. This type of open failure has been a rather common failure in this specific TSV process.


Gaudestad J.,Neocera LLC | Orozco A.,Neocera LLC
Microelectronics Reliability | Year: 2014

Due to magnetic fields ability to penetrate through all materials used by the semiconductor industry, a unique ability not found in any other techniques, it has become an important technique for detecting shorts, leakages and opens in multi stacked Through Silicon Via samples. We show in this paper how Magnetic Field Imaging is being used to image the current in a TSV stacked silicon device with a new 3D analysis algorithm of the distance from the top of the stacked device to the current path. © 2014 Elsevier Ltd. All rights reserved.


Gaudestad J.,Neocera LLC | Orozco A.,Neocera LLC | Chen J.,Honyang Global Technology Co.
IEEE International Reliability Physics Symposium Proceedings | Year: 2015

Magnetic Current Imaging (MCI) and static Thermal Emission (TE), two commonly used Electrical Fault Isolation (EFI) tools, are compared on their ability to localize a short defect in a mobile device central processing unit (CPU). The short was localized by MCI between two micro bumps below the 100μm thick silicon die while TE detected a thermal signal slightly offset due to laser scribing on the die surface. © 2015 IEEE.


Gaudestad J.,Neocera LLC | Orozco A.,Neocera LLC | Kimball M.,Maxim Integrated | Gopinadhan K.,National University of Singapore | Venkatesan T.,National University of Singapore
Proceedings of the International Symposium on the Physical and Failure Analysis of Integrated Circuits, IPFA | Year: 2014

Magnetic Current Imaging (MCI) has been used for more than a decade to localize shorts and leakages in packages non-destructively. Now that packages are becoming more complex with multiple dies inside the same package, MCI is showing its effectiveness in localizing these complicated shorts non-destructively when the Failure Analysis (FA) engineer does not know from Automated Test Equipment (ATE) if the fault location is in the die or package or which die. We show in this paper that the FA lab can be simplified by the introduction of MCI as a one stop Fault Isolation (FI) tool for all shorts and leakages. © 2014 IEEE.


An RF DC SQUID based magnetometer capable of sensing coherent magnetic fields up to 200 MHz and higher is developed which overcomes frequency limitations associated with noise signals due to transmission line delays between the SQUID circuit and readout electronics. The bandwidth limitations are overcome by superimposing the RF flux on the modulation flux to produce at the SQUID output a binary phase modulated RF voltage, which is processed to lock the static flux, and to control modulation regime by producing an AC bias for the RF flux. RF readout electronics based on a double lock-in technique (sequential demodulation of the RF SQUID voltage at the modulation flux frequency _(m )and the RF flux frequency _(RF)), yields a signal proportional to the product of amplitude and phase cosine of RF flux with linear dynamic range up to five orders in magnitude if compared to DC SQUID operated in traditional flux-locked loop regime.


High quality GaN films exhibiting strong room temperature blue photoluminescence with negligible impurity emissions are grown by a Pulsed Laser Deposition process in which process parameters are controlled to attain plasma particle energy of a target material plume directed from the target on the substrate structure below 5 eV at the deposition surface. Among the process parameters, a distance between the deposition surface and the target, a pressure level of the reaction gas in the processing chamber, and an energy density of the pulsed laser beam directed to the target are controlled, in combination, to attain the required low plasma particle energy of the plume below 5 eV in vicinity of the deposition surface.

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