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Tokyo Institute of Technology high-k/ In.53 Ga.47 As MOS - Defect Analysis of high-k/in.53 G a.47 As MOS Capacitor using capacitance voltage method,,, Darius Zade,,, Parhat Ahmet,,,,,,

~InGaAs high-k ~ SiO (~.nm) Si EOT~.nm excess leakage current HfO SiO x layer (.5~.7nm) Si EOT~.9nm Present stage Higher-k in Direct Contact Si EOT~.5nm Continous Scaling for Future Electronics EOT~.5nm nm W La O 3 k=3 La-silicate k=8~4 5 o C, 3 min EOT:Equivalent oxide thickness Higher-k in Direct Contact III-V sub. Green Nanoelectronics high-k HfO La O 3 Si In.53 Ga.47 As Si In.53 Ga.47 As (cm /Vs) 6 (ev)..74 Si-MOS high-k In.53 Ga.47 As Ref. Dae-Hyun Kim et. al, ECS., ()

本研究の目的 C-V特性とコンダクタンス法を用いて電気特性から周波数分散の原因を検討 In.53Ga.47As-MOSキャパシタ欠陥モデル InGaAs基板の欠陥が影響しているのではないか 3

~High-k/Si SiO /Si ~ G ω ωgc p m ox = Gm + ω ( Cox Cm) D it.5 Gp q ω max : G p /ω (F/cm ) i 3-6 E-E -9 i =. ev SiO /Si peak SiO in low frequency La-Silicate/Si 3 4 5 6 7 Frequency (Hz) 4 ~ 5 Hz Hz 5 4 3 Time Constant (s) - -3-4 -5-6 -7-8 Ref,, τ ot τ it Oxide -...4 E-E i (ev) Si E c E f interface states (D it ) E V oxide bulk trap (D ot ) Si() Oxide traps interface traps 4

C-V (D it ) D it C-V W/HfO /n- In.53 Ga.47 As MOS CAP 5

~In.53 Ga.47 As MOS ~ n- or p-in.53 Ga.47 As/InP HF (NH 4 ) S (electron beam deposition) HfO nm 8 In-situ RF W Reactive ion etching(rie) Al F.G( N :H = 97%:3% ) 37 o C5min 6

HfO /In.53 Ga.47 As C-V Capacitance (µf/cm ).5.5 PMA in F.G. (a) p- type khz~ MHz.5 PMA in F.G. (b) n- type khz~ MHz.5 - - 5 µm 5 µm 5 µm 5 µm Gate Voltage (V) - -.5 - -.5.5 -.5 - -.5.5.5 Gate Voltage (V) Gate Voltage (V) W/HfO /n- or p- In.53 Ga.47 As C-V J (A/cm ) - -3-5 -7-9 n-type p-type W HfO (nm) In.53 Ga.47 As p n 7

High-k/ n- In.53 Ga.47 As Conductance G p /ω (F/cm ) 3-7 3 K.5-5 3 K (a) (b) -.7 V ~ -.3 V. V ~.5 V -.7 V 3 4 5 6 Frequency (Hz).5.5 -.3 V 5 µm 5 µm 5 µm 5 µm 3 4 5 6 Frequency (Hz) InGaAs 8

(n- type) G p /ω (F/cm ) HfO /n- In.53 Ga.47 As MOS CAP 3-5 (a) 4 K.V.4.7.5.3.. (b) 7 K.V (c) 77 K (d) 77 K.5V.V.5V.V W HfO (nm) In.53 Ga.47 As.45V.4V 3 4 5 6 Frequency (Hz) Capacitance (µf/cm ) (e) khz~ MHz 4 K -.5.5 Gate voltage (V) (f) E c 5 khz~ MHz 77 K -.5.5 Gate voltage (V) C-V : 9

W/HfO /n- In.53 Ga.47 As MOS CAP : Bulk Trap : Interface trap E c V g > ψ B =.7 ev E f.37 ev E BT E i E v.74 ev E f (ψ s >. ev) N A = 8 6 Equivalent Circuit C ox C it C acc G it C BT G BT E BT E f E BT

InGaAs InGaAs

JST

TEM W PMA at 4 o C. nm HfO n-in.53 Ga.47 As defects W HfO InGaAs W HfO In.53 Ga.47 As HfO defect nm nm InGaAs HfO /InGaAs 3

n-, p-type CV characteristics Capacitance (µf/cm ) Capacitance (µf/cm ).5 PMA in F.G. (a) khz~ MHz.5 PMA in F.G. (b) khz~ MHz.5.5 - - 5 µm 5 µm 5 µm 5 µm Gate Voltage (V) - -.5 - -.5.5 -.5 - -.5.5.5 Gate Voltage (V) Gate Voltage (V) PMA in F.G. PMA in F.G. (c) (d) khz~ MHz khz~ MHz.5.5 J (A/cm ) - -3-5 -7-9 n-type p-type - - 5 µm 5 µm 5 µm 5 µm Gate Voltage (V) - -.5 - -.5.5 -.5 - -.5.5.5 Gate Voltage (V) Gate Voltage (V) J (A/cm ) - -3-5 -7-9 n-type p-type

XPS 5

(p- type) HfO /p- In.53 Ga.47 As MOS CAP 6-6 3 K. -6 7 K.9-6 77 K (a) -.8 V (b) -. V (c) -.6 V -.4 V - V -.8 V - V -.8 V -.6 V G p /ω (F/cm ) 4.8 V.5 V. V.8.4.4 V.8 V.6.3.6 V 3 4 5 6 3 4 5 6 3 4 5 6 Frequency (Hz) Frequency (Hz) Frequency (Hz) p- type 6

k-value La O 3 K eff 5 HfO K eff 9 7

G p / (µf/cm ) 5.E 6 4.E 6 4.E 6 3.E 6 3.E 6.E 6.E 6.E 6 5.E 7 defect A 4-7 -5 3 defect C. V -.7 V defect B.E+ Frequency ( Hz ) defect A : oxide bulk traps defect B : interface states 3 4 5 6 defect B defect C V g > E f PMA in F.G. nm C ox : Interface states : Bulk Trap C acc C it G it C BT G BT W HfO n-in.53 Ga.47 As defects E c E BT E f E i E v W HfO InGaAs defect C : substrate bulk traps 8

-3 E BT Time Constant (s) -4-5 -6-7 77K p-type 3K 4 K n-type 77 K..4.6.8 E-E v (ev) V g > E f E f V g < n- type : Bulk Trap : Mid-gap interface traps 3K low temp E c E f E v E c E f E i E v E BT low temp (ψ s >. ev) N D = 7 p- type 9

τ e = τ t exp( E/ kt) Trapped charge response time Charge carrier trapping time constant: σ τ t = συ t N :capture cross section: 6 cm υ t :thermal velocity: e:5.5 5 h:. 5 Nc ~ = 4.8.( m / m ) T ( cm ) 5 3/ 3/ 3 Γ Nv ~ = 4.8.( m / m ) T ( cm ) 5 3/ 3/ 3 h n N N E k T / i = ( c. v) exp( g /( B )) :. 7 :5.5 8 :~.

~High-k ~ La O 3 /Ge MOS C-V Capacitance (µf/cm ) W La O 3 (5nm) Ge khz khz PMA in N Frequency Dispersion < % peak D it : 5 µm 5 µm 5.4 3 cm - ev - -.5 - -.5.5.5 Gate voltage (V)

G p /ω (F/cm ) 5.E 6 4 4.E 6 4.E 6 3 3.E 6 3.E 6.E 6.E 6.E 6 5.E 7-7 -5 HfO /InGaAs khz 5 khz 3 4 5 6 -.5 -.5 Frequency ( Hz ) Gate Voltage ( V ).E+.5 Capacitance (µf/cm ) Hump hysteresis Strech-out Accumulation frequency dispersion Oxide (bulk or border) Interface states Semiconductor bulk C acc C dep C ox C it G it C ox C it G it C BT G BT C ot G ot 3

border traps 4

D it : G ω p m ox = Gm + ω ( Cox Cm) D it ωgc.5 Gp q ω max 5

(D it ) Quasi-static D it D it C-V C-V D it Dieter K. Schroder: Semiconductor Material and Device Characterization 3rd Edition (6). : ~ LSI ~ (99). 6

Weak Fermi-level pinning Mid-Gap Dit Mid-Gap 4 o C,5min (with Si) D it [ev - cm - ] 3 8 6 4 5 o C,5min (with Si) p-type n-type..4.6.8 E [ev] 7

3nm 3nm () () p-type In.53 Ga.47 As InP n-type In.53 Ga.47 As InP # (p) (n) InGaAs InP (Buffer) Handle 3nm x 7 (Zn) 3nm x 8 (Zn) 5µm 5x 8 (Zn) 3nm 8x 6 (Si) 3nm 3x 8 (Si) 35µm 5x 8 (S) 8

.Series Resistance R s (contact, substrate..) measured capacitance C m device capacitance C = ( GR ) ( ) c c s + + ω CR c s parallel conductance (Nicollian&Brews). Fermi Level Pinning) 9

τ p = υσ p ps Carrier C it = ( τ ) p Density of holes Hole capture cross secion Hole capture time Accumulation p s capture time( τ p ) C it qd it Depletion τ p C it C = [( C + C ) + C ] tot it sub ox 3

InGaAs high-k Al O 3 cm - /ev high-k MG Al O 3 III-V Sub. MG High-k III-V Sub. Al O 3 La O 3 Capacitance ( F/cm ) 3.5.5.5 La O 3 /n-ingaas CV khz khz khz MHz W-FLP D it - - Gate Voltage (V) 3

InGaAs MOS Mid-Gap D it Weak Fermi-level pinning Ref. Hwang et. al, APL. Lett. 96, 9 () Weak Fermi-level pinning (WFLP) Ref. Martens et. al, MICROELEC. 84 (7) 46-49 Mid-Gap D it Ref. APL. 96, 9 () 33

(D it ) Quasi-static D it D it C-V C-V D it Dieter K. Schroder: Semiconductor Material and Device Characterization 3rd Edition (6). : ~ LSI ~ (99). 34

La O 3 high-k/si La O 3 ( r =3.4) (E g =5.6eV) Silicate high-k/si 5 o C, 3 min J. A. Ng et al.: IEICE Electronics Express 3 (6) 36 La-silicate La-silicate/Si nm La O 3 35

Interface States D it [ev - cm - ] 3 4 o C,5min (with Si) 8 6 4 5 o C,5min (with Si) p-type..4.6.8 E [ev] Increasing towards mid-gap More effective for Conduction band Response frequency (Hz).E+ 9.E+9 6.E+6 3.E+3.E+ -3.E-3.E-6-9.E-9 Electron Hole -6 p-type n-type..4.6.8 E v Trap energy (ev) E c n-type E g =.74eV 36

XPS 37