Mechanisms of IonizationInduced Carrier Transport and Collection in NextGeneration IIIV Structures

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Mechanisms of Ionization-Induced Carrier
Transport and Collection in Next-Generation
III-V Structures

• Dale McMorrow
• Radiation Effects Section
• Naval Research Laboratory
• Washington, DC

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Outline

• Objectives/Overview
• Motivation
• III-V Technology Overview
• Radiation Effects in III-V Technologies
• NextGen III-V Research Program
• Technology Transfer

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Description of the Effort

• ABCS Antimonide-Based Compound Semiconductors
• To investigate, using both theory and experiment,
  the basic mechanisms of ionization-induced
  carrier deposition, transport, and collection in
  next-generation antimonide-based III-V compound
  semiconductor structures and materials
• This is a collaborative effort between the Naval
  Research Laboratory and Vanderbilt University

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Status of the Effort

• Significant ongoing ABCS technology development
• DARPA ABCS Program (2001-2006)
• DARPA ISIS Program (2007-present)
• Intel CRADA
• Very little is understood about the performance
  of ABCS technologies in hostile environments
• Experimental and theoretical databases are
  minimal
• NRL has unique access to Sb-based technology, and
  has developed the experimental approaches
  necessary to address their response to ionizing
  radiation
• Vanderbilt is ideally suited to take the lead on
  the theory/computational part of this effort

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III-V Semiconductor Material Systems
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III-V Semiconductor Material Systems
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Motivations ABCS Electronics
High-speed, low-power consumption electronics are
needed for light-weight power supplies, extension
of battery lifetimes, and high data rate
transmission

• Low-noise receivers
• space-based sensing and communications
• portable communications
• micro-air-vehicles (MAVs)

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Motivations ABCS Electronics

• High-speed logic circuits
• high-speed onboard processing
• communications, data transmission
• potential for lowest power-delay product
• integration with RTDs for enhanced functionality
  and low-voltage operation
• InP HEMTs presently hold the record current gain
  cutoff frequency for any three-terminal device

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Motivations ABCS Electronics

• Sb-based electronics exhibit
• High electron mobility
• High electron velocity
• High sheet charge density
• Large conduction band offset
• lt0.5 V operation / low power dissipation
• Low noise
• Digital circuits with speeds gt100 GHz are
  anticipated

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ABCS Technology Development

• The NRL Microwave Technology Branch is a world
  leader in the growth, fabrication and
  characterization of Sb-based HEMTs, p-channel
  HFETs, and HBTs.
• DARPA ABCS Program (2001-2006)
• NRL teamed with Northrop-Grumman Space Technology
  (NGST, formerly TRW) to develop next-generation
  high-speed, low-power HEMT and HBT technology
  using antimonide heterostructures.
• At the inception of the ABCS program, NRL had
  been in the forefront of the development of
  antimonide HEMT technology for more than seven
  years.
• NRLs superior material growth and device
  processing capabilities let to a record high
  cutoff frequency fT of 250 GHz, and a 90 GHz fT
  at a record low voltage of 0.1 volts
• NRL growth and processing technology for
  antimonide HEMTs transferred to NGST via CRADA in
  FY03.

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ABCS Technology Development

• DARPA ABCS Program Major Milestones
• demonstration of an antimonide HEMT with a record
  maximum frequency of oscillation (fmax 275 GHz)
  
• Demonstration of an order of magnitude less power
  consumption than HEMTs based on competitive
  semiconductor material systems
• The first antimonide-based X-band and W-band
  MMICs with state-of-the-art low-power performance

Ref J. Vac. Sci. Technol. B, 17 (3), May 1999
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ABCS Technology Development

• DARPA Integrated Structure is Sensor (ISIS)
  Program
• NRL is again teamed with NGST
• Continue to develop next-generation high-speed,
  low-power Sb-based HEMT technology.
• Intel CRADA
• NRL is also currently teamed with Intel, via a
  Cooperative Research and Development Agreement
  (CRADA), to develop advanced p-channel Sb HFETs
  for use in high-speed complementary logic
  applications

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ABCS Technology InAs HEMT
6.1 Å Lattice Spacing

• 1.7 mm AlSb buffer layer on GaAs (SI) substrate
  accommodates 8 lattice mismatch
• InSb-like interfaces high electron mobility
• Modulation doping in thin InAs(Si) layer
  sheet charge densities of 1-4 x 1012/cm2
• Large InAs/InAlAs valence band offset lower
  leakage current from holes
• InAs sub-channel reduces impact ionization
  higher frequency operation

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III-V Semiconductor Material Systems
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ABCS Technology InAsSb HEMT
InAsSb HEMT has attractive material properties
and unique design flexibility enabling improved
high-speed, low-power performance

• Higher electron mobility and velocity for higher
  speed.
• Type I band alignment for lower leakage and lower
  noise figure.
• Reach peak velocity at lower electric field for
  lower power consumption.
• Complete structure is stable in air for increased
  stability.

6.2 Å Lattice Spacing
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Radiation Effects in III-V FETs

• III-V FETs typically are tolerant to high levels
  of ionizing radiation
• Lack of native oxides
• Dominated by displacement damage (DD) effects
• III-V FET-based technologies typically are
  extremely susceptible to single-event effects
• A primary goal of this program is to develop an
  understanding of the basic mechanisms of carrier
  transport and collection that lead to this SEE
  susceptibility

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Rad Effects TID/DD in III-V FETs

• Recent work at NRL demonstrates that 6.1 Å ABCS
  technology is more tolerant than either GaAs or
  InP-based technologies
• Due to strong carrier confinement
• in heterostructure wells
• Weaver, et al., High tolerance of
• InAs/AlSb high-electron-mobility
• transistors, Appl. Phys. Lett, 87,
• 173501 (2005).

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Rad Effects SEE in III-V FETs

• GaAs MESFETs and HFETs Extensive work in 1990s
• Experiment and Simulation (NRL and others)
• Charge collection and enhancement mechanisms
  fairly well understood
• InP HEMTs Limited experimental and simulation
  work
• Experimental data similar to that of GaAs devices
  (NRL)
• Simulation results inadequate but reveal
  significant differences
• ABCS Devices
• HI and pulsed laser data on 6.1 Å technology
  (NRL)
• No simulation results on 6.1 Å technology
• No data/simulation on 6.2 Å or 6.3 Å technologies

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Rad Effects CC in GaAs HFETs
Charge Enhancement
100 fC
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Rad Effects CC in GaAs HFETs
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Rad Effects CC in GaAs HFETs

• 10X - 60X charge enhancement observed
• HI and laser excitation
• Associated with S-D current (from power supply)
• Barrier lowering at source-substrate barrier
• device turned on
• Associated with charge deposited below active
  region
• 1 mm to 2 mm most effective
• Current pathway from source, deep through
  substrate, to drain

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Rad Effects CC in InP HEMTs
1e18 (600 ps)
Carrier Injection and S-D Current Confined to
InGaAs Channel
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Rad Effects CC in InP HEMTs
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Rad Effects Bulk vs. HEMTs
Bulk (GaAs MESFET)
InP HEMT
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Rad Effects AlSb/InAs HEMTs
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Technical Approach

• OBJECTIVE To investigate, using both theory and
  experiment, the basic mechanisms of
  ionization-induced carrier deposition, transport,
  and collection in next-generation
  antimonide-based III-V compound semiconductor
  structures and materials.
• APPROACH
• Experiment measurement of charge collection
  transients in 6.1 Å and 6.2 Å ABCS test
  structures
• Theory develop a theoretical description to
  describe the highly non-equilibrium state induced
  in heterosructure devices by ionizing radiation
  use the experimental data to validate and
  calibrate the theory

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Technical Approach

• Experimental Approach (NRL)
• Test structure selection
• Packaging in high-bandwidth packages
• High-bandwidth transient measurement
• Statistical analysis of ion-induced transients
• Theoretical Approach (VU)
• Develop a theoretical description
• Evaluate capabilities of various commercial codes
  and determine suitability
• Use the experimental data to validate and
  calibrate the theory
• Identify the basic mechanisms of carrier
  transport and collection that are responsible for
  shaping the data

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Technical Approach

• High-bandwidth (12-20 GHz), single-shot transient
  measurement
• Permits direct measurement of ion-induced
  transients for single ion strikes for the first
  time

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Technical Approach

• Theoretical Approach (VU)
• One graduate student assigned to this project
  (Sandeepan DasGupta)
• Vanderbilt will provide access to its Advanced
  Computing center for Research and Education
  (ACCRE), which houses their Beowulf cluster
  supercomputer

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Progress

• Initial test structures selected
• Mounted in high-bandwidth packages
• Tested for dc operational characteristics
• Heavy-Ion test scheduled for June
• Vanderbilt student (Sandeepan DasGupta) is
  getting started
• Reading literature
• Evaluating available commercial codes
• Asking questions

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Key Personnel

• NRL Solid State Electronics Branch
• Radiation Effects Branch (McMorrow, Warner)
• NRL Microwave Technology Branch
• Brad Boos
• Vanderbilt/ISDE
• Robert Reed
• Ron Schrimpf
• Grad student

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Technology Transfer

• NRL ABCS technology development program
• ISDE Engineering
• Collaborative RD, e.g. NRL/Vanderbilt
• DoD vendor relationships
• NASA Goddard
• Through students