The Impact of Nitrogen Engineering in Silicon Oxynitride Gate Dielectric on Negative-Bias Temperature Instability of p-MOSFETs: A Study by Ultrafast On-The-Fly IDLINI_{\rm DLIN}IDLIN Technique (original) (raw)
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I E E E Transactions on Electron Devices, 2008
Degradation of p-MOSFET parameters during negative-bias temperature instability (NBTI) stress is studied for different nitridation conditions of the silicon oxynitride (SiON) gate dielectric, using a recently developed ultrafast on-the-fly I DLIN technique having 1-µs resolution. It is shown that the degradation magnitude, as well as its time, temperature, and field dependence, is governed by nitrogen (N) density at the Si/SiON interface. The relative contribution of interface trap generation and hole trapping to overall degradation as varying interfacial N density is qualitatively discussed. Plasma oxynitride films having low interfacial N density show interface trap dominated degradation, whereas relative hole trapping contribution increases for thermal oxynitride films having high N density at the Si/SiON interface.
2009
Negative Bias Temperature Instability (NBTI) is studied in plasma (PNO) and thermal (TNO) Si-oxynitride devices having varying EOT. Threshold voltage shift (∆V T ) and its field (E OX ), temperature (T) and time (t) dependencies obtained from no-delay on-the-fly linear drain current (I DLIN ) measurements are carefully compared to that obtained from Charge Pumping (CP). It is shown that thin and thick PNO and thin TNO devices show very similar NBTI behavior, which can primarily be attributed to generation of interface traps (∆N IT ). Thicker TNO devices show different NBTI behavior, and can be attributed to additional contribution from hole trapping (∆N h ) in pre-existing bulk traps. A physics based model is developed to explain the experimental results.
Journal of Applied Physics, 2005
The interface trap generation ͑⌬N it ͒ and fixed oxide charge buildup ͑⌬N ot ͒ under negative bias temperature instability ͑NBTI͒ of p-channel metal-oxide-semiconductor field-effect transistors ͑pMOSFETs͒ with ultrathin ͑2 nm͒ plasma-nitrided SiON gate dielectrics were studied using a modified direct-current-current-voltage method and a conventional subthreshold characteristic measurement. Different stress time dependences were shown for ⌬N it and ⌬N ot. At the earlier stress times, ⌬N it dominates the threshold voltage shift ͑⌬V th ͒ and ⌬N ot is negligible. With increasing stress time, the rate of increase of ⌬N it decreases continuously, showing a saturating trend for longer stress times, while ⌬N ot still has a power-law dependence on stress time so that the relative contribution of ⌬N ot increases. The thermal activation energy of ⌬N it and the NBTI lifetime of pMOSFETs, compared at a given stress voltage, are independent of the peak nitrogen concentration of the SiON film. This indicates that plasma nitridation is a more reliable method for incorporating nitrogen in the gate oxide.
IEEE Transactions on Electron Devices, 2000
Impact of gate dielectric processing [plasma and thermal nitridation, nitrogen total dose, effective oxide thickness (EOT)] on negative-bias temperature instability (NBTI) degradation and recovery is studied. The magnitude, field, and temperature dependence of NBTI is measured using no-delay I DLIN method and carefully compared to charge-pumping measurements. Plasma (thin and thick EOT) and thermal (thin EOT) oxynitrides show very similar temperature and time dependence of NBTI generation, which is identical to control oxides and is shown to be due to generation of interface traps. NBTI enhancement for oxynitride films is shown to be dependent on nitrogen concentration at the Si-SiO 2 interface and plasma oxynitrides show lower NBTI compared to their thermal counterparts for same total nitrogen dose and EOT. Both fast and slow NBTI recovery components are shown to be due to recovery of generated interface traps. Recovery fraction reduces at lower EOT, while for similar EOT oxynitrides show lower recovery with-respect-to control oxides. NBTI generation and recovery is explained with the framework of reaction-diffusion model. Index Terms-Charge pumping (CP), fractional recovery (FR), hole trapping, interface traps, negative-bias temperature instability (NBTI), on-the-fly I DLIN , reaction-diffusion (R-D) model, thermal and plasma oxynitrides.
IEEE Transactions on Electron Devices, 2008
An ultrafast on-the-fly technique is developed to study linear drain current (I DLIN) degradation in plasma and thermal oxynitride p-MOSFETs during negative-bias temperature instability (NBTI) stress. The technique enhances the measurement resolution ("time-zero" delay) down to 1 μs and helps to identify several key differences in NBTI behavior between plasma and thermal films. The impact of the time-zero delay on time, temperature, and bias dependence of NBTI is studied, and its influence on extrapolated safe-operating overdrive condition is analyzed. It is shown that plasma-nitrided films, in spite of having higher N density, are less susceptible to NBTI than their thermal counterparts. Index Terms-Field acceleration, negative-bias temperature instability (NBTI), plasma oxynitride, p-MOSFET, safe-operating voltage, temperature activation, thermal oxynitride, time exponents. I. INTRODUCTION T HE negative-bias temperature instability (NBTI) of device parameters (linear drain current I DLIN , threshold voltage V T , transconductance G M , etc.) is a serious reliability issue for Si oxynitride (SiON) p-MOSFETs [1]-[14]. Similar to other degradation mechanisms, the NBTI lifetime is determined by recording device parameter degradation during accelerated stress test and subsequently using suitable bias and time-dependent models [15]-[24] to extrapolate measured data from stress (high voltage, short time) to operating (low voltage, long time) conditions. However, unlike other degradation mechanisms, NBTI degradation recovers substantially once the stress is removed [25], [26]. Therefore, the conventional stress-measure-stress (SMS) technique (interrupting stress at logarithmic time intervals and performing transfer I-V sweep Manuscript
IEEE Transactions on Electron Devices, 2000
An ultrafast on-the-fly technique is developed to study linear drain current (I DLIN ) degradation in plasma and thermal oxynitride p-MOSFETs during negative-bias temperature instability (NBTI) stress. The technique enhances the measurement resolution ("time-zero" delay) down to 1 μs and helps to identify several key differences in NBTI behavior between plasma and thermal films. The impact of the time-zero delay on time, temperature, and bias dependence of NBTI is studied, and its influence on extrapolated safe-operating overdrive condition is analyzed. It is shown that plasma-nitrided films, in spite of having higher N density, are less susceptible to NBTI than their thermal counterparts.