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

Abstract

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.

Out-of-Plane Strain Effects on Physically Flexible FinFET CMOS

“…7(b-c)). This is in line with previous observations by Choi et al on the reduction in the work function of TiN due to tensile out-of-plane bending which reduces the Gate/Oxide barrier height causing higher leakage currents [17].…”

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

“…Under gate injection, applied tensile ͑compressive͒ stress decreases ͑increases͒ the tunneling barrier height of electrons from gate to substrate via TaN gate work function shift, resulting in an increase ͑decrease͒ in gate leakage current. 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.…”

A Thermodynamic Entropy Approach to Reliability Assessment with Applications to Corrosion Fatigue

“…Meanwhile, the anodic current at the electrode surface can decrease near-surface work hardening and increase the mobility of dislocation, ultimately stimulating fatigue damage [14,15,58]. The strain response of electrode potential or work function has long been of interest in relation to a wide range of problems, including corrosion in structural materials under load [14,[82][83][84] and coupling of electronic properties to stress in semiconductor devices [85,86], and to diffusion [87,88] and metallurgy [89]. Gutman [14] and Sahal et al [84] suggested that the local value of the chemical potential in the liquid/solid system is defined only by the absolute value of the hydrostatic part of the stress tensor, , and is independent of the deviatory part of the stress.…”