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Abstract: Combining simultaneously on the fly interface-trap (OTFIT) and the reverse voltage variation of source and drain (S/D) during measurement phase of measure/stress/measure (MSM) sequences, we have been able to scan the negative bias temperature instability (NBTI) across the channel length of PMOS transistors. In addition, we have analyzed the generation and evolution of interface-trap distribution with respect to the transistor gate length. We have found that NBTI-induced interface-trap density, ΔNit are not uniform along the channel. The experimental results reveal an evident propagation of the NBTI degradation. This propagation starts from S/D channel edges and penetrates into the channel center. It is accelerated by temperature and electric field until saturation. However, field-accelerated propagation seems more important than temperature-accelerated one. Further, transistors with shorter channel length degrade more rapidly than those with longer channel length. We have also shown that the channel length has a great effect on NBTI features such as the apparent activation energy and time power-law exponent. These results suggest that diffusion-limited process is not the sole source of the time degradation dependence, but also gate length have to be taken into account. [Copyright &y& Elsevier]

Abstract: Charge-pumping (CP) techniques with various rise and fall times and with various voltage swings are used to investigate the energy distribution of interface-trap density and the bulk traps. The charge pumped per cycle (Q cp) as a function of frequency was applied to detect the spatial profile of border traps near the high-k gate dielectric/Si interface and to observe the phenomena of trap migration in the high-k dielectric bulk during constant voltage stress (CVS) sequence. Combining these two techniques, a novel CP technique, which takes into consideration the carrier tunneling, is developed to measure the energy and depth profiles of the border trap in the high-k bulk of MOS devices. [Copyright &y& Elsevier]

Novel gate-to-drain nonoverlapped-implantation (NOI) nMOSFETs have been developed as potential multibit-per-cell nonvolatile-memory (NVM) devices. The lateral charge distribution of the NOI NVM device programmed by channel hot electron injection is investigated by charge-pumping (CP) techniques with presumed interface trap distributions. For the first time, the CP results have revealed the lateral charge distribution and trapping density at the NOI's programmed state. The maximum trapping charge density locates near its drain junction. The charge distribution is estimated about 90 nm in length and spread widely over the NOI region. Two-dimensional simulators with charge bars using the same charge trapping distribution confirm the experimental results by fitting their IDS — VG curves. [ABSTRACT FROM AUTHOR]

The charge-pumping technique is used for the characterization of the lateral charge distribution in non-volatile memory devices that are based on localized trapping of charge. The lateral charge distribution is calculated directly from charge-pumping measurements using a deconvolution-based procedure. Memory cells employing either a silicon-rich-oxide or Si3N4 trapping medium have been analyzed. Electrons are injected into the trapping medium using channel-hot-electron-injection. The influence of programming pulse width, retention time and device channel length on the lateral charge distribution has been investigated. [Copyright &y& Elsevier]

In this paper, the Oxide-Trap based on Charge-Pumping (OTCP) extraction method is extended from high frequencies (HFs) to low frequencies (LFs). As a consequence, the LF-OTCP method simultaneously senses both interface-trap and border-trap (switching oxide-trap) in charge-pumping (CP) current (Icp) measurements. We have found that radiation-induced oxide-trap (ΔNot) is dependent on ΔVth (threshold voltage shift), ΔIcpm,h (augmentation of maximum CP current at high frequencies), and ΔIcpm,l (augmentation of maximum CP current at low frequencies), where ΔIcpm,l is caused by radiation-induced interface-trap increase (ΔNit) and ΔIcpm,t by both radiation-induced interface and border-trap increases (ΔNit) and (ΔNbt), respectively. We have shown that ΔIcpm,l and ΔIcpm,h can be easily obtained from a vertical shift of the charge-pumping curve at low and high frequencies respectively, and ΔVth from a lateral one. [ABSTRACT FROM AUTHOR]

In this paper, we propose a new extraction method of radiation-induced oxide-trap density (ΔNot), called Oxide-Trap based on Charge-Pumping (OTCP). This part presents the HF-OTCP method, which relies on high-frequency (HF) standard charge-pumping measurement. By applying an HF gate voltage signal, we avoid the border-trap effect in CP current (Icp) measurements. Hence, Icp will be only due to the interface-trap contribution. We establish, using the HF-OTCP method, that ΔNot is only dependent on ΔVth (threshold voltage shift) and ΔIcpm (increase of maximum CP current), where δIcpm is caused by radiation-induced interface-trap increase (ΔNit ). We also clearly show that ΔVth and ΔIcpm can be obtained from lateral and vertical shifts of Elliot's charge-pumping curves, respectively. Thus, this new procedure allows the determination of ΔNot without needing any additional techniques. Finally, this procedure can be used in rapid hardness assurance test to evaluate both radiation-induced oxide and interface traps. [ABSTRACT FROM AUTHOR]