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Search Publications by: Pragya Shrestha (Fed)

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Displaying 26 - 47 of 47

Analysis and Control of RRAM Overshoot Current

January 15, 2018
Author(s)
Pragya R. Shrestha, David M. Nminibapiel, Jason P. Campbell, Jason T. Ryan, Dmitry Veksler, Helmut Baumgart, Kin P. Cheung
To combat the large variability problem in RRAM,current compliance elements are commonly used to limit the inrush current during the forming operation. Regardless of the compliance implementation (1R-1R or 1T-1R), some degree of current overshoot is

Ferroelectricity in Polar Polymer-based FETs: A Hysteresis Analysis

January 15, 2018
Author(s)
Vasileia Georgiou, Dmitry Veksler, Jason Campbell, Jason Ryan, Pragya Shrestha, D. E. Ioannou, Kin P. Cheung
There is an increasing number of reports on polar polymer-based Ferroelectric Field Effect Transistors (FeFETs), where the hysteresis of the drain current - gate voltage (Id-Vg) curve is investigated as the result of the ferroelectric polarization effect

Highly Efficient Rapid Annealing of Thin Polar Polymer Film Ferroelectric Devices at Sub-Glass Transition Temperature

December 18, 2017
Author(s)
Vasileia Georgiou, Dmitry Veksler, Jason T. Ryan, Jason P. Campbell, Pragya R. Shrestha, D. E. Ioannou, Kin P. Cheung
An unexpected rapid anneal of electrically active defects in an ultra-thin (15.5 nm) polar polyimide film at and below glass transition temperature (Tg) is reported. The polar polymer is the gate dielectric of a thin-film-transistor (TFT). Gate leakage

Towards reliable RRAM performance: macro- and microscopic analysis of operation processes

November 9, 2017
Author(s)
Gennadi Bersuker, Dmitry Veksler, David M. Nminibapiel, Pragya Shrestha, Jason Campbell, Jason Ryan, Helmut Baumgart, Maribeth Mason, Kin P. Cheung
Resistive RAM technology promises superior performance and scalability while employing well- developed fabrication processes. Conductance is strongly affected by structural changes in oxide insulators that make cell switching properties extremely sensitive

Impact of RRAM Read Fluctuations on the Program-Verify Approach

May 22, 2017
Author(s)
David M. Nminibapiel, Dmitry Veksler, Pragya Shrestha, Jason Campbell, Jason Ryan, Helmut Baumgart, Kin P. Cheung
The stochastic nature of the conductive filaments in oxide-based resistive memory (RRAM) represents a sizeable impediment to commercialization. As such, program-verify methodologies are highly alluring. However, it was recently shown that program-verify

Cryogenic pulsed I-V measurements on homo- and heterojunction III-V TFETs

April 1, 2017
Author(s)
Quentin Smets, Jihong Kim, Jason Campbell, David M. Nminibapiel, Dmitry Veksler, Pragya Shrestha, Rahul Pandey, Anne S. Verhulst, Eddy Simoens, David J. Gundlach, Curt A. Richter, Kin P. Cheung, Suman Suman, Anda Mocuta, Nadine Collaert, Aaron Thean, Marc Heyns
Most experimental reports of tunneling field-effect transistors show defect-related performance degradation. Charging of oxide traps causes Fermi level pinning, and Shockley-Read-Hall (SRH)/trap-assisted tunneling (TAT) generation cause unwanted leakage

Characteristics of Resistive Memory Read Fluctuations in Endurance Cycling

January 23, 2017
Author(s)
David M. Nminibapiel, Dmitry Veksler, Pragya R. Shrestha, Jihong Kim, Jason P. Campbell, Jason T. Ryan, Helmut Baumgart, Kin P. Cheung
We report on new fluctuation dynamics of the high resistance state of Hafnia-based RRAM devices after RESET. We observe that large amplitude fluctuations occur more frequently immediately after programming and their frequency of occurrence decays in the

Rapid and Accurate C-V Measurements

October 1, 2016
Author(s)
Jihong Kim, Pragya Shrestha, Jason Campbell, Jason Ryan, David M. Nminibapiel, Joseph Kopanski, Kin P. Cheung
We report a new technique for the rapid measurement of full capacitance-voltage (C-V) characteristic curves. The displacement current from a 100 MHz applied sine-wave, which swings from accumulation to strong inversion, is digitized directly using an

Compliance-Free Pulse Forming of Filamentary RRAM

September 30, 2016
Author(s)
Pragya Shrestha, David M. Nminibapiel, Jihong Kim, Helmut Baumgart, Kin (Charles) Cheung, Jason Campbell
Despite the overwhelming effort to improve the efficacy of resistive random access memory (RRAM), the underlying physics governing RRAM operation have proven elusive. A survey of the recent literature almost universally indicates that the remaining glaring

Electron Spin Resonance Scanning Probe Spectroscopy for Ultra-Sensitive Biochemical Studies

April 22, 2015
Author(s)
Jason P. Campbell, Jason T. Ryan, Pragya R. Shrestha, Zhanglong Liu, Canute I. Vaz, Jihong Kim, Vasileia Georgiou, Kin P. Cheung
Electron spin resonance (ESR) spectroscopy’s affinity for detecting paramagnetic free radicals, or spins, has been increasingly employed to examine a large variety of biochemical interactions. Such paramagnetic species are broadly found in nature and can

Accurate Fast Capacitance Measurements for Reliable Device Characterization

July 1, 2014
Author(s)
Pragya R. Shrestha, Kin P. Cheung, Jason P. Campbell, Jason T. Ryan, Helmut Baumgart
As device dimensions continue to scale, transient phenomena are becoming increasingly more important to understand for both performance and reliability considerations. Recently, fast capacitances versus voltage (CV) measurements have been gaining attention

Energy Control Paradigm for Compliance-Free Reliable Operation of RRAM

June 5, 2014
Author(s)
Pragya R. Shrestha, David M. Nminibapiel, Jihong Kim, Jason P. Campbell, Kin P. Cheung, Shweta Deora, G. Bersuker, Helmut Baumgart
We demonstrate reliable RRAM operation by controlling the forming energy via short voltage pulses (picosecond range) which eliminates the need for a current compliance element. We further show that the dissipated energy during forming and SET/RESET

Accurate RRAM Transient Currents during Forming

April 30, 2014
Author(s)
Pragya R. Shrestha, David M. Nminibapiel, Jason P. Campbell, Jihong Kim, Canute I. Vaz, Kin P. Cheung, Helmut Baumgart
Current overshoot during forming has been shown to be a serious issue. Recently the current overshoot duration has been shown to be an important factor impacting device performance. Short duration overshoot in the range of ns yield better performance. But

Dependence of the Filament Resistance on the Duration of Current Overshoot

March 3, 2014
Author(s)
Pragya R. Shrestha, David M. Nminibapiel, Jason P. Campbell, Kin P. Cheung, Helmut Baumgart, Shweta Deora, G. Bersuker
The characteristics of a conductive filament in HfO2 RRAM is shown to be dependent on the duration of the current compliance overshoot, which may occur during the filament formation process. In addition to the overshoot amplitude, the filament resistance

Fast-Capacitance for Advanced Device Characterization

March 3, 2014
Author(s)
Pragya R. Shrestha, Kin P. Cheung, Jason T. Ryan, Jason P. Campbell, Helmut Baumgart
Fast-CV measurements are frequently being used to study transient phenomena associated with advanced devices. In this study, we show that many artifacts plague this measurement and then provide a proper method to legitimize fast-CV measurements as

Unexpected effect of thermal storage observed on SiC power DMOSFET

September 29, 2013
Author(s)
Zakariae Chbili, Pragya R. Shrestha, Jason P. Campbell, John S. Suehle, Kin P. Cheung, D. E. Ioannou
In this paper we report an unexpected improvement in the SiC DMOSFET transistor characteristics after a long temperature treatment at 150 C. The evolution of the device characteristics during a TDDB stress is compared to that after an elevated temperature

Current Compliance Circuit to Improve Variation in ON State Characteristics and to Minimize RESET Current

October 7, 2012
Author(s)
Pragya R. Shrestha, Adaku Ochia, Jason P. Campbell, Canute I. Vaz, Jihong Kim, Kin P. Cheung, Helmut Baumgart, Gary Harris
The wide distribution of ON and OFF values and high SET current in resistive memory is attributed to the high current overshoot during the SET process. In this paper we show a circuit which is capable of precisely limiting the current during SET process

High Speed Endurance and Switching Measurements for Memristive Switches

March 6, 2012
Author(s)
Pragya R. Shrestha, Adaku Ochia, Kin P. Cheung, Jason P. Campbell, Helmut Baumgart, Gary Harris
Accurate capture of the Set/Reset characteristics is a necessary but challenging task for the development of memristive switches. Here we describe and demonstrate a technique capable of meeting this challenge. This technique can measure the transient

High Speed Switching Characteristics of Pt/Ta2O5/Cu Memristive Switch

October 8, 2011
Author(s)
Pragya R. Shrestha, Adaku Ochia, Kin P. Cheung, Jason P. Campbell, Helmut Baumgart, Gary Harris
Accurate measurements of the transient details of switching a memristive switch are crucial to the elucidation of the switching mechanism. Such high-speed measurements are often plagued by artifacts. Here we describe a measurement technique capable of