Strain induced changes in gate leakage current and dielectric constant of nitrided Hf-silicate metal oxide semiconductor capacitors

Abstract

Uniaxial-mechanical-stress altered gate leakage current and dielectric constant of silicon metal-oxide-semiconductor (MOS) devices with nitrided Hf-silicate (HfSiON) dielectric are measured as a function of uniaxial stress applied using four-point wafer bending along the [110] direction. The gate leakage current and dielectric constant are found to increase by ∼2% per 100MPa of tensile and compressive stresses. A decrease in hole trap activation energy in hafnium oxide-based dielectric is used to explain the mechanical stress altered gate leakage. It is proposed that the HfSiON dielectric constant increase results from band gap narrowing caused by strain induced N p band splitting.

Reliability of HfSiON gate dielectric silicon MOS devices under [110] mechanical stress: Time dependent dielectric breakdown

“…4,11,20 The mechanical stress dependence on t BD can be investigated further by ͑1͒ monitoring the relative change in gate injection current of HfSiON Si MOS device as a function of applied mechanical stress 5 and ͑2͒ mechanical stress-induced increase in HfSiON/Si interface trap generation during CVS. 11 In our previous work, 13 we already observed an increase in the gate injection current in HfSiON Si MOS capacitors, based on the Poole-Frenkel emission, under both tensile and compressive stresses, matching with our mechanical stress dependence on t BD in this work. Hence, it is consistent with the observation that an increase in gate injection current results in a decrease in t BD .…”

“…13 Samples with gate areas of 0.000 857, 0.0016, 0.0026, and 0.0052 cm 2 are used. Constant negative gate voltage stress-ing is performed with a gate leakage current compliance limit of 10 pA using a Keithley 4200 dc characterization system.…”

Reliability characterization of stress-induced charge trapping in HfO2 by electrostatic discharge impulse stresses

“…On the other hand, the Poole-Frenkel ͑PF͒ emission recently was demonstrated as the ruling conduction mechanism in Hf-based dielecrics. 7,8 In this work, however, the PF emission can only be observed at high temperature ͑Ն478 K͒, as shown in the inset of Fig. 2.…”

Total Ionizing Dose Effects on Strained ${\rm HfO}_{2}$-Based nMOSFETs

“…A possible explanation of these results is that compressive and tensile uniaxial mechanical stress both lower the hole trap energy level in and/or , reducing hole trapped charges. In recent work, trap-assisted gate tunneling current in high-k MOS capacitors increased under both compressive and tensile stress [24], suggesting that the hole trap energy distribution may be shifted to lower average values by uniaxial mechanical stress. In addition, an increase in trap assisted tunneling in thin (2.5 nm) results from reduced trap activation energy due to both compressive and tensile stress [25].…”