Development of an Ultrafast On-the-Fly $I_{\rm DLIN}$ Technique to Study NBTI in Plasma and Thermal Oxynitride p-MOSFETs

Abstract

Abstract-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.

On the thermal activation of negative bias temperature instability

“…Similarly, during recovery, discharging occurs earlier than the measurement window [11,12]. We remark that reports exist claiming that the minimum time constants are in the order of 1µs [13,14]; however, this is not in agreement with other data that show degradation and recovery are already in full flight at 1µs [10][11][12].…”

A Common Framework of NBTI Generation and Recovery in Plasma-Nitrided SiON p-MOSFETs

“…The details of the UF-OTF I DLIN setup have been presented in [5]. During stress, the measured I DLIN transients at…”

“…4 shows (RHS) the measured power-law time exponent (n) during long-time stress as a function of stress T , which is obtained by the conventional MSM method at various delays [8], as well as OTF (t 0 = 1 ms) [7] and UF-OTF (t 0 = 1 μs) [5] methods. It is now well known that recovery during measurement delay causes an increase in n [1], [7], [8].…”

“…Recently, degradation during NBTI stress on p-MOSFETs having wide range of SiON processes (variation in nitrogen (N) density and thickness) has been studied [4] using an ultrafast on-the-fly (UF-OTF) I DLIN method [5]. Based on these results, SiON process dependence has been attributed to the relative differences in trapped holes (ΔV h 's) in preexisting bulk insulator traps and generation of interface traps (ΔV IT 's) that contribute to the overall ΔV T .…”

“…In this letter, NBTI degradation and recovery in PN SiON p-MOSFETs are studied using the UF-OTF I DLIN method [5]. A strong process-dependent correlation between stress and recovery is demonstrated.…”