Opposing dependence of the electron and hole gate currents in SOI MOSFETs under uniaxial strain

Zhao, Wei; Seabaugh, Alan; Adams, V.; Jovanovic, D.; Winstead, B.

doi:10.1109/led.2004.848118

Cited by 53 publications

(12 citation statements)

References 14 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The data are also in good agreement with the thick virtual substrate devices reported in Ref. [35][36][37]. Strained Si devices fabricated on thick virtual substrates with varying ͓Ge͔ and thicker gate oxides ͑6 nm͒ in Ref.…”

Section: Strain-induced Leakage Reductionssupporting

confidence: 88%

Improved gate oxide integrity of strained Si n-channel metal oxide silicon field effect transistors using thin virtual substrates

Ling

Olsen

Escobedo-Cousin

et al. 2008

Journal of Applied Physics

View full text Add to dashboard Cite

Articles you may be interested inSuper critical thickness SiGe-channel heterostructure p -type metal-oxide-semiconductor field-effect transistors using laser spike annealing Study of strain relaxation in Si/SiGe metal-oxide-semiconductor field-effect transistors J. Appl. Phys. 97, 114504 (2005); 10.1063/1.1922582 Hole mobility enhancements and alloy scattering-limited mobility in tensile strained Si/SiGe surface channel metal-oxide-semiconductor field-effect transistors This work presents a detailed study of ultrathin gate oxide integrity in strained Si metal oxide silicon field effect transistors ͑MOSFETs͒ fabricated on thin virtual substrates aimed at reducing device self-heating. The gate oxide quality and reliability of the devices are compared to those of simultaneously processed Si control devices and conventional thick virtual substrate devices that have the same Ge content ͑20%͒, strained Si channel thickness, and channel strain. The thin virtual substrates offer the same mobility enhancement as the thick virtual substrates ͑ϳ100% compared to universal mobility data͒ and are effective at reducing device self-heating. Up to 90% improvement in gate leakage current is demonstrated for the strained Si n-channel MOSFETs compared to that for the bulk Si controls. The lower leakage arises from the increased electron affinity in tensile strained Si and is significant due to the sizeable strain generated by using wafer-level stressors. The strain-induced leakage reductions also lead to major improvements in stress-induced leakage current ͑SILC͒ and oxide reliability. The lower leakage current of the thin and thick virtual substrate devices compares well to theoretical estimates based on the Wentzel-Kramers-Brillouin approximation. Breakdown characteristics also differ considerably between the devices, with the strained Si devices exhibiting a one order of magnitude increase in time to hard breakdown ͑T HBD ͒ compared to the Si control devices following high-field stressing at 17 MV cm −1 . The strained Si devices are exempted from soft breakdown. Experimental based analytical leakage modeling has been carried out across the field range for the first time in thin oxides and demonstrates that Poole-Frenkel ͑PF͒ emissions followed by Fowler-Nordheim tunneling dominate gate leakage current at low fields in all of the devices. This contrasts to the frequently reported assumption that direct tunneling dominates gate leakage in ultrathin oxides. We also show that PF emissions are reduced in strained Si devices compared to bulk Si devices. The gate leakage, interface trap density, bulk oxide traps, breakdown characteristics, and SILC are further improved in the thin virtual substrate devices compared to the thick virtual substrate devices. The difference is attributed to surface roughness. The thick virtual substrates exhibit characteristic cross-hatching morphology, whereas the thin virtual substrates do not since they relax primarily through point defects rather than misfit dislocations. Virtual substrate growth tech...

show abstract

Section: Strain-induced Leakage Reductionssupporting

confidence: 88%

Improved gate oxide integrity of strained Si n-channel metal oxide silicon field effect transistors using thin virtual substrates

Ling

Olsen

Escobedo-Cousin

et al. 2008

Journal of Applied Physics

View full text Add to dashboard Cite

show abstract

“…15 Under substrate injection, mechanical stress-induced electron repopulation between ⌬ 2 and ⌬ 4 subbands in the n-type inversion layer changes the out-of-plane effective mass and tunneling barrier height of electrons in ⌬ subbands as previously reported. [16][17][18][19] During CVS for thin SiO 2 ͑Ͻ2.5 nm͒, energetic electrons were injected from gate to the Si substrate, breaking dangling bonds in the ͓111͔ direction, normally passivated by hydrogen at P b0 and P b1 centers at near the SiO 2 / ͑100͒Si interface. 9 These additional defects increase trap-assisted tunneling currents.…”

Section: Impact Of Mechanical Stress On Direct and Trap-assisted Gatementioning

confidence: 99%

Impact of mechanical stress on direct and trap-assisted gate leakage currents in p-type silicon metal-oxide-semiconductor capacitors

Choi

Nishida

Thompson

2008

Applied Physics Letters

View full text Add to dashboard Cite

Articles you may be interested inPlasma-assisted atomic layer deposition of TiN / Al 2 O 3 stacks for metal-oxide-semiconductor capacitor applications Lifetime-limited current in Cu-gate metal-oxide-semiconductor capacitors subjected to bias thermal stress J. Appl. Phys. 99, 034504 (2006); 10.1063/1.2168034 Quantum-mechanical study of the direct tunneling current in metal-oxide-semiconductor structures J. Appl. Phys. 98, 024506 (2005); 10.1063/1.1985976 Suppressed shot noise in trap-assisted tunneling of metal-oxide-semiconductor capacitors

show abstract

“…24 The band splitting at low stress and moderate to high gate bias is set by confinement. 6,8 For tensile stress, the hole tunneling current enhancements of both Ge and Si devices result from hole repopulation into E 2 , which has a smaller tunneling barrier height ͑ B,2 Ͻ B,1 ͒ and out-of-plane effective mass ͑m E 2 z Ͻ m E 1 z ͒. 23 Applied tensile stress causes the E 1 to E 2 band splitting to decrease, resulting in hole repopulation from E 1 to E 2 , as shown in Fig.…”

Section: A Stress-altered Hole Tunneling Currents Of Ge and Si P-mosmentioning

confidence: 99%

“…[1][2][3] Strained Ge is a potential replacement for strained Si for future nanoscale p-MOSFETs ͑metal-oxide-semiconductor field-effect transistors͒. [6][7][8][9] For p-MOSFETs, uniaxial tensile stress increases while compressive stress decreases the gate tunneling current. [6][7][8][9] For p-MOSFETs, uniaxial tensile stress increases while compressive stress decreases the gate tunneling current.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Impact of mechanical stress on gate tunneling currents of germanium and silicon p-type metal-oxide-semiconductor field-effect transistors and metal gate work function

Choi

Numata

Nishida

et al. 2008

Journal of Applied Physics

View full text Add to dashboard Cite

Articles you may be interested inFluorine implantation for effective work function control in p -type metal-oxide-semiconductor high-k metal gate stacks J. Vac. Sci. Technol. B 29, 01A905 (2011); 10.1116/1.3521471 Low temperature mobility in hafnium-oxide gated germanium p -channel metal-oxide-semiconductor field-effect transistors Appl. Phys. Lett. 91, 263512 (2007); 10.1063/1.2828134 Physics of strain effects in semiconductors and metal-oxide-semiconductor field-effect transistors Strain-induced changes in the gate tunneling currents in p -channel metal-oxide-semiconductor field-effect transistors Appl. Phys. Lett. 88, 052108 (2006); 10.1063/1.2168671Modeling and characterization of direct tunneling hole current through ultrathin gate oxide in pmetal-oxide-semiconductor field-effect transistors Uniaxial four-point wafer bending stress-altered gate tunneling currents are measured for germanium ͑Ge͒/silicon ͑Si͒ channel metal-oxide-semiconductor field-effect transistors ͑MOSFETs͒ with HfO 2 / SiO 2 gate dielectrics and TiN/ P+ poly Si electrodes. Carrier separation is used to measure electron and hole currents. The strain-altered hole tunneling current from the p-type inversion layer of Ge is measured to be ϳ4 times larger than that for the Si channel MOSFET, since the larger strain-induced valence band-edge splitting in Ge results in more hole repopulation into a subband with a smaller out-of-plane effective mass and a lower tunneling barrier height. The strain-altered electron tunneling current from the metal gate is measured and shown to change due to strain altering the metal work function as quantified by flatband voltage shift measurements of Si MOS capacitors with TaN electrodes.

show abstract

Opposing dependence of the electron and hole gate currents in SOI MOSFETs under uniaxial strain

Cited by 53 publications

References 14 publications

Improved gate oxide integrity of strained Si n-channel metal oxide silicon field effect transistors using thin virtual substrates

Improved gate oxide integrity of strained Si n-channel metal oxide silicon field effect transistors using thin virtual substrates

Impact of mechanical stress on direct and trap-assisted gate leakage currents in p-type silicon metal-oxide-semiconductor capacitors

Impact of mechanical stress on gate tunneling currents of germanium and silicon p-type metal-oxide-semiconductor field-effect transistors and metal gate work function

Contact Info

Product

Resources

About