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Full-Band/Full-Wave Simulations of InGaAs-based Pseudomorphic HEMTs
Full-Band/Full-Wave Simulations of InGaAs-based Pseudomorphic HEMTs
Full-Band/Full-Wave Simulations of InGaAs-based Pseudomorphic HEMTs
Full-Band/Full-Wave Simulations of InGaAs-based Pseudomorphic HEMTs
Full-Band/Full-Wave Simulations of InGaAs-based Pseudomorphic HEMTs
Full-Band/Full-Wave Simulations of InGaAs-based Pseudomorphic HEMTs
Full-Band/Full-Wave Simulations of InGaAs-based Pseudomorphic HEMTs
Full-Band/Full-Wave Simulations of InGaAs-based Pseudomorphic HEMTs
Full-Band/Full-Wave Simulations of InGaAs-based Pseudomorphic HEMTs
Full-Band/Full-Wave Simulations of InGaAs-based Pseudomorphic HEMTs
Full-Band/Full-Wave Simulations of InGaAs-based Pseudomorphic HEMTs
Full-Band/Full-Wave Simulations of InGaAs-based Pseudomorphic HEMTs
Full-Band/Full-Wave Simulations of InGaAs-based Pseudomorphic HEMTs
Full-Band/Full-Wave Simulations of InGaAs-based Pseudomorphic HEMTs
Full-Band/Full-Wave Simulations of InGaAs-based Pseudomorphic HEMTs
Full-Band/Full-Wave Simulations of InGaAs-based Pseudomorphic HEMTs
Full-Band/Full-Wave Simulations of InGaAs-based Pseudomorphic HEMTs
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Full-Band/Full-Wave Simulations of InGaAs-based Pseudomorphic HEMTs

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  • 1. Nanostructures Research GroupCENTER FOR SOLID STATE ELECTRONICS RESEARCH 1ARIZONA INSTITUTE FOR NANOELECTRONICS
  • 2. 2007 F. Schwierz and J.J. Liou, Modern microwaveNanostructures Research Group transistors: theory, design, and performance, JohnCENTER FOR SOLID STATE ELECTRONICS RESEARCH Wiley & Sons, Inc., New Jersey, 2003. 2ARIZONA INSTITUTE FOR NANOELECTRONICS
  • 3. 6 4 energ y [eV]•  Hybrid CMC/EMC approach •  M. Saraniti and S.M. Goodnick, IEEE TED, 47, 2 1909 (2000) 0•  Bandstructure: -2 •  empirical pseudopotential method. -4 EMC •  local, nonlocal, and spinorbit interactions. -6 CMC L Γ X U,K Γ•  Full phonon spectra: •  valence shell model. wave vector Hybrid/MC performance ratio time per iter. [sec/5000 e ] -•  Scattering mechanisms: •  Deformation potential (optical/acoustic) •  Polar optical phonons. •  Impurity scattering (Ridley model).•  Poisson solver: •  Multi-grid Nanostructures Research Group CENTER FOR SOLID STATE ELECTRONICS RESEARCH field [V/m] 3 ARIZONA INSTITUTE FOR NANOELECTRONICS
  • 4. Strained In0.75Ga0.25As Eg = 0.57 eVNanostructures Research GroupCENTER FOR SOLID STATE ELECTRONICS RESEARCH 4ARIZONA INSTITUTE FOR NANOELECTRONICS
  • 5. LSD = 0.30 µm dg = gate-to-channel separation Vd = 0.8 VNanostructures Research GroupCENTER FOR SOLID STATE ELECTRONICS RESEARCH 5ARIZONA INSTITUTE FOR NANOELECTRONICS
  • 6. z H G ( 1800 y c n e 1600 u q L = 20 nm G e 1400 r Small signal F fT (GHz) 1200 analysis i (t) f f o L = 35 nm G D t u 1000 G v (t) C S 800 L = 70 nm G J. S. Ayubi-Moak, et al., IEEE TED,v (t) 600 54(9), pp. 2327-38, Sept. 2007. i (t) ΔV 10 -1 10 0 Source-Drain Spacing (µm) 0 T 0 T Lg=50 nm Lg=10 nmfT=1.3 THz fT=2.2 THzNanostructures Research GroupCENTER FOR SOLID STATE ELECTRONICS RESEARCH 6ARIZONA INSTITUTE FOR NANOELECTRONICS
  • 7. z K.S. Yee, IEEE Trans. Antennas Propagat., 14(302) 1966 “Yee cell”Maxwell’s equations •  Most direct explicit solution of Ey Maxwell’s equations available (i.e.  Ex Ex no matrix inversion required).  Hz ∂H Ez∇ × E = −µ Ex Ey •  A complete “full-wave” method ∂t Hx without approximation (i.e. no  Hy Hy pre-selection of output modes or  ∂E  Ez Ex solution form necessary.)∇× H = ε +J Ex Hx Ey Ex y ∂t Hz Ey xPML Absorbing Boundary Conditions • 

“artificial” anisotropic electric/magnetic* conductivities within domain boundaries allow for absorption/attenuation waves. •  Numerical “split-field” approach allowing perfect transmission into absorbing layer (regardless of frequency, polarization, or angle of incidence). Nanostructures Research Group CENTER FOR SOLID STATE ELECTRONICS RESEARCH 7 J. P. Bérenger, IEEE Trans. Antennas Propagat., 44(110) 1996. ARIZONA INSTITUTE FOR NANOELECTRONICS
  • 8. Task 0 Setup Parallel Region Initial Scatter Task 1 Task N BCs BCs BCs calc H field calc H field calc H field calc E field calc E field calc E field Communication – plane exchange Output & FinishNanostructures Research GroupCENTER FOR SOLID STATE ELECTRONICS RESEARCH 8ARIZONA INSTITUTE FOR NANOELECTRONICS
  • 9. y x 2D slice εr = 12.0 z •  Photonic crystals/PBM shown great deal of promise for true integrated optics. •  Waveguides with small bends possible making compact integrated photonic circuits (IPCs) achievable. εr = 1.0 a3D MIT structure Nanostructures Research Group CENTER FOR SOLID STATE ELECTRONICS RESEARCH 9 ARIZONA INSTITUTE FOR NANOELECTRONICS
  • 10. Source plane 370 x 520 x 50 grid Bipolar pulse ~107 grid points Si slab (εr =12.0)Nanostructures Research Group 44 cylinders (εr =6.0)CENTER FOR SOLID STATE ELECTRONICS RESEARCH 10ARIZONA INSTITUTE FOR NANOELECTRONICS
  • 11. PML d Air Top View of Coupled Simulation Domain: SiN GATE SiN DRAINSOURCE SOURCE In 0.53 Ga 0.47 As In 0.53 Ga 0.47 As (cap) (cap) Excitation Source Plane In 0.52 Al0.48 As (barrier) δ − doping d (spacer)PML InAs PML GATE DRAIN In 0.75 Ga 0.25 As (channel) In 0.52 Al0.48 As (buffer) 15 µm InP (substrate) SOURCE GROUND PLANE SiN SiN S.I. Substrate S.I. Substrate 15 µm Nanostructures Research Group CENTER FOR SOLID STATE ELECTRONICS RESEARCH 11 ARIZONA INSTITUTE FOR NANOELECTRONICS
  • 12. PML d Air Top View of Coupled Simulation Domain: SiN GATE SiN DRAINSOURCE In 0.53 Ga 0.47 As In 0.53 Ga 0.47 As SOURCE (cap) (cap) Excitation In 0.52 Al0.48 As (barrier) Source δ − doping PlanePML (spacer) PML d InAs In 0.75 Ga 0.25 As (channel) GATE DRAIN In 0.52 Al0.48 As (buffer) InP (substrate) 15 µm Nanostructures Research Group SOURCE CENTER FOR SOLID STATE ELECTRONICS RESEARCH 12 ARIZONA INSTITUTE FOR NANOELECTRONICS
  • 13. Steps full-wave simulation:FDTD:  Initialization  ∂H∇ × E = −µ ∂t 1. Obtain quasi-static dc solution for dc bias point  (CMC/Poisson) and store E fields and J.  ∂E ∇× H = ε +J 2. Initialize H field in FDTD solver using: ∂t  ∇× E = 0CMC:   ∇ × H dc = J dc 1 ⎛ N (i , j ,k ) ⎞J (i, j , k ) = ⎜ ∑ S n vn ⎟ ΔxΔyΔz ⎜ n =1 ⎟ 3.  Apply excitation source and begin updating ⎝ ⎠ fields:   J tot ∂E 1 ∂t ε [  ac  tot  dc = ∇× H − J − J ( )] FDTD  CMC ∂H 1    = − ∇× E (Etot , H tot ) ∂t µ Nanostructures Research Group CENTER FOR SOLID STATE ELECTRONICS RESEARCH 13 ARIZONA INSTITUTE FOR NANOELECTRONICS
  • 14. Excitation method: • 

Voltage on gate (or drain) in perturbed (Gaussian pulse, sinusoid, step voltage). •  Transverse E-fields (Ex, Ez ) computed via 2D Poisson solver (SOR) and applied to source plane at each timestep.
 z
 y
 x
 Nanostructures Research Group CENTER FOR SOLID STATE ELECTRONICS RESEARCH 14 ARIZONA INSTITUTE FOR NANOELECTRONICS
  • 15. Nanostructures Research GroupCENTER FOR SOLID STATE ELECTRONICS RESEARCH 15ARIZONA INSTITUTE FOR NANOELECTRONICS
  • 16. •  Simulations suggest fT well above 1 THz for 10-50 nm gate pHEMTs with source-to-drain spacing of 300 nm.• Analysis of average carrier velocity under the gate suggests an effective gate length that becomes important for small gate length devices.•  3D domain decomposition/parallel processing required for realistic simulation times using coupled simulator. Nanostructures Research Group CENTER FOR SOLID STATE ELECTRONICS RESEARCH 16 ARIZONA INSTITUTE FOR NANOELECTRONICS
  • 17. •  3D decomposition works best for more general geometries and particularly for large problem domains ( >108 grid cells) Nanostructures Research Group CENTER FOR SOLID STATE ELECTRONICS RESEARCH 17 ARIZONA INSTITUTE FOR NANOELECTRONICS

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