Plasmonic Noise of Field-Effect Transistors Operating at Terahertz - - PowerPoint PPT Presentation
Plasmonic Noise of Field-Effect Transistors Operating at Terahertz Frequencies C. Palermo, A. Mahi, H. Marinchio, L. Varani University of Montpellier, France P. Shiktorov, E. Starikov, V. Gruzhinskis Semiconductor Physics Institute, Vilnius,
University of Montpellier, France
Semiconductor Physics Institute, Vilnius, Lithuania
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BOUNDARY MODES
closed complex even mixed
f dc response STABLE
DETECTION Homodyne Heterodyne
Non resonant f ac/dc response Resonant
OUTPUT
UNSTABLE
EMISSION Self oscillations Multiplication
f power
dc voltage ac voltage THz radiation Optical excitation ac carriers generation INPUT 2 source drain gate insulator plasma waves Material + geometry
∂n ∂t + ∂nv ∂x = 0 ∂v ∂t + ∂ ∂x v2 2 + e m∗ ϕ
∂x + vν = ˜ f
Continuity Hydrodynamic
Effective mass Relaxation rate Diffusion Langevin force
m∗ ν D ˜ f
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δ
εc ∂2ϕ ∂x2 + εs Ug − ϕ d(x)δ = e ε0 [n(x) − ND(x)]
Pseudo 2D Poisson
Channel thickness Gate distance 3D 2D
d(x) dδ → 0 dδ → ∞ δ
longitudinal transverse
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Voltage driven Current driven
( ϕ(0) = 0 ϕ(L) = VD ( ϕ(0) = 0
∂E(L,t) ∂t
=
1 εcε0 [jtot − en(L, t)v(L, t)]
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Open circuit Closed Circuit Complex charge
Z = R + jX
2 4 6 1 3 5
Sξξ(ω) = Z L n(x0)|Gξ(ω, x0)|2Sff(x0)dx0 ξ = ( U Voltage J Current
Noise source
4kBTν m∗
Spectral response function
Voltage and Current Local contribution Admittance,Impedance
Y , Z δSξξ SUU, SJJ
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7
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Impedance field
SUU(f) = 4kBT<[Z(f)]
drain (10-21 V2m2s)
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1 2 3 4 5 6
frequency
1 2 3 4 5 δ ≠ 0 δ = 0
0.01 0.1 1 10 5 10 15 20 25 SUU
drain (10-21 V2m2s)
f (THz)
2D hybrid 3D channel 3D contacts
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modes
modes
0.5 1 1.5 2 2.5 1 2 3 4 5 6 7 8 9 10 SJJ (10-8 A2s/m2) f (THz)
1 3 5 2 4 6 2 4 6
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1 2 3 100 200 300 400 f1 (THz) Lg (nm)
0.1 0.2 0.3 0.5 1 1.5 2 SUU
drain (10-21 V2m2s)
f (THz)
Gate shortening
source drain gate
Lg Ln Ln
≃1/Lg ≃1/(Lg+2Ln)
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102 104 106 108 1010 1012 δSJJ
gate (arb.units)
100 101 102 103 104 100 200 300 400 500 600 δSUU
drain (arb.units)
x0 (nm)
S D Gate
δSξξ = n(x0)|Gξ(ω, x0)|2Sff(x0)
Local contribution
Sξξ(ω) = Z L δSξξdx0
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equilibrium
1 2 3 4 5 1 2 3 4 5 6 7 8 SJJ (10-8 A2sm-2) f (THz)
excited
plasma waves source drain gate insulator Optical excitation ac carriers generation
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0.1 1 10 100 2 4 6 8 10 12 14 Frequency (THz) ϕ = 180o ϕ = 0o Average (μA)
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0.15 0.2 0.25 0.3 0.35 0.4 0.45 2 4 6 8 10 12 14 16 18 20 Uds (V) t (ps)
Stable Unstable
0.01 0.1 1 10 100 0.5 1 1.5 2 SUU
drain (10-21 V2m2s)
f (THz)
Increasing current
Gate V I Source Drain
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