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Electron spin resonance (ESR) spectroscopy measures paramagnetic free radicals, or electron spins, in a variety of biological, chemical, and physical systems. Detection of diverse paramagnetic species is important in applications ranging from quantum computation to biomedical research. Countless efforts have been made to improve the sensitivity of ESR detection. However, the improvement comes at the cost of experimental accessibility. Thus, most ESR spectrometers are limited to specific sample geometries and compositions. Here, we present a nonresonant transmission line ESR probe (microstrip geometry) that effectively couples high frequency microwave magnetic field into a wide range of sample geometries and compositions. The nonresonant transmission line probe maintains detection sensitivity while increasing availability to a wider range of applications. The high frequency magnetic field homogeneity is greatly increased by positioning the sample between the microstrip signal line and the ground plane. Sample interfacing occurs via a universal sample holder which is compatible with both solid and liquid samples. The unavoidable loss in sensitivity due to the nonresonant nature of the transmission line probe (low Q) is recuperated by using a highly sensitive microwave interferometer-based detection circuit. The combination of our sensitive interferometer and nonresonant transmission line provides similar sensitivity to a commercially available ESR spectrometer equipped with a high-Q resonator. The nonresonant probe allows for transmission, reflection, or dual-mode detection (transmission and reflection), where the dual-mode results in a √2 signal enhancement.

The polarization switching speed of ferroelectric (FE) hafnium zirconium oxide (HZO) is studied with the device size down to sub-μm in lateral dimension. Ultrafast measurement of transient switching current on metal-ferroelectric-metal (MFM) device with a crossbar array or a single crossbar structure is performed to analyze the switching dynamics. A record fast polarization switching of 360 ps is achieved for 15 nm thick HZO with 0.1 μm2 crossbar array device structure. The observed record switching speed is found to be limited by domain wall propagation speed in the nucleation limited switching process. It is further verified after significant reduction of RC delay of the devices and the implementation of crossbar array structure.

Carbon nanotubes (CNT) resistance-change memory devices were assessed for neuromorphic applications under high frequency use conditions by employing the ultra-short (100 ps -10 ns) voltage pulse technique. Under properly selected operation conditions, CNTs demonstrate switching characteristics promising for various NN implementations.

We report on a novel semiconductor reliability technique that incorporates an electrically detected magnetic resonance (EDMR) spectrometer within a conventional semiconductor wafer probing station. EDMR is an ultrasensitive electron paramagnetic resonance technique with the capability to provide detailed physical and chemical information about reliability limiting defects in semiconductor devices. EDMR measurements have generally required a complex apparatus, not typically found in solid-state electronics laboratories. The union of a semiconductor probing station with EDMR allows powerful analytical measurements to be performed within individual devices at the wafer level. Our novel approach replaces the standard magnetic resonance microwave cavity or resonator with a small non- resonant near field microwave probe. Using this new approach we have demonstrated bipolar amplification effect and spin dependent charge pumping in various SiC based MOSFET structures. Although our studies have been limited to SiC based devices, the approach will be widely applicable to other types of MOSFETs, bipolar junction transistors, and various memory devices. The replacement of the resonance cavity with the very small non- resonant microwave probe greatly simplifies the EDMR detection scheme and allows for the incorporation of this powerful tool with a wafer probing station. We believe this scheme offers great promise for widespread utilization of EDMR in semiconductor reliability laboratories.

We observe a gamma-irradiation-induced change in electrically detected magnetic resonance (EDMR) in TiN/Ti/HfO2/TiN resistive random access memory (RRAM). EDMR measurements exclusively detect electrically active defects, which are directly involved in the transport mechanisms within these devices. The EDMR response has an isotropic g value of 2.001 ± 0.0003. The response increases dramatically with increased gamma irradiation. We tentatively associate this EDMR response with spin-dependent trap-assisted tunneling events at O2− centers coupled to hafnium ions. Although our study cannot fully identify the role of these defects in electronic transport, the study does unambiguously identify changes in transport defects caused by the ionizing radiation on defects involved in electronic transport in RRAM devices. This paper also contributes more broadly to the RRAM field by providing direct, though incomplete, information about atomic scale defects involved in electronic transport in leading RRAM systems.

Resistive random access memory (RRAM) technology promises superior performance and scalability while employing well-developed fabrication processes. Conductance in insulating oxides employed in RRAM devices can be strongly affected by atomic-level changes that makes cell switching properties extremely sensitive to operation conditions inducing local structural modifications. This opens an opportunity to condition the memory cell stack by forming a conductive filament capable of high frequency, low energy switching. Certain materials with pre-existing conductive paths, in particular some polycrystalline oxides, like hafnia, are shown to respond well to this approach. For this class of materials, the concept of ultra-fast pulse technique as an ultimate method for assessing RRAM switching capabilities in circuitry operations is discussed. Hafnia-based cells demonstrate compliance-free (1R) forming with no current overshoot, low operation currents, and reduced variability.

Switching variability in polycrystalline compliance-free HfO 2 -based 1R RRAM is evaluated employing ultra-fast low voltage pulse approach. Changes in filament conductivity are linked to the variations of energy consumed in a switching process. This study indicates that variability is reduced (suppressed) in more resistive filaments.

In this paper we report TDDB results on SiO2/SiC MOS capacitors fabricated in a matured production environment. A key feature is the absence of early failure out of over 600 capacitors tested. The observed field accelerations and activation energies are higher than what is reported on SiO2/Si of similar oxide thickness. The great improvement in oxide reliability and the deviation from typical SiO2/SiC observations are explained by the quality of the oxide in this study.

We report multi-level MoTe 2 based resistive random-access memory (RRAM) devices with switching speeds of less than 5 ns due to an electric-field induced 2H to 2H d phase transition. Different from conventional RRAM devices based on ionic migration, the MoTe 2 -based RRAMs offer intrinsically better reliability and control. In comparison to phase change memory (PCM)-based devices that operate based on a change between an amorphous and a crystalline structure, our MoTe 2 -based RRAM devices allow faster switching due to a transition between two crystalline states. Moreover, utilization of atomically thin 2D materials allows for aggressive scaling and high-performance flexible electronics applications. Multi-level stable states and synaptic devices were realized in this work, and operation of the devices in their low-resistive, high-resistive and intrinsic states was quantitatively described by a novel model.

In this work, ultrafast pulses with pulse widths ranging from 100 ps to seconds were applied on the gate of Ge ferroelectric (FE) nanowire (NW) pFETs with FE Hf 0.5 Zr 0.5 O 2 (HZO) gate dielectric exhibiting steep subthreshold slope (SS) below 60 mV/dec bi-directionally. With applied gate bias pulses (V G = -1 to -10 V), high-mobility Ge drain current was monitored as a test vehicle to capture the polarization switching of HZO. It was found that HZO could switch its polarization directly by a single pulse with the minimum pulse width of 3.6 ns. The polarization switching triggered by pulse train with pulse width as short as 100 ps was demonstrated for the first time.

We report on a novel semiconductor reliability technique that merges electrically detected magnetic resonance (EDMR) with a conventional semiconductor wafer probing station. This union with a semiconductor probing station allows EDMR measurements to be performed at the wafer level. Our measurements forgo a microwave cavity or resonator for a very small non-resonant near field microwave probe [1]. Bipolar amplification effect (BAE) [4] and spin dependent charge pumping (SDCP) [5] were demonstrated on various SiC MOSFET structures. These measurements were made via frequency-swept EDMR. The elimination of the resonance cavity, and incorporation with a wafer probing station, greatly simplifies the EDMR detection scheme and offers promise for widespread EDMR adoption in semiconductor reliability laboratories.

The low processing temperature of polymeric materials and their wide range of applications make polar polymer based ferroelectric memory very promising and attractive. The typical configuration of the ferroelectric memory cell is the FeFET (Ferroelectric field-effect-transistor) with the polar polymer incorporated in the gate dielectric stack. The memory effect in these devices originates from the polarization of the ferroelectric polymer film and results in a hysteresis of the Id-Vg characteristics. In this study, we fabricated FeFETs based on ultrathin poly-Si channel and CP1- polymer (glass-transition temperature (Tg ~260 C) as the gate dielectric. We investigated the hysteresis of the Id-Vg curves over a wide range of temperatures and frequencies. We observed the effects of thermocycling on the device, such as the change of the hysteresis loop direction at temperatures close to Tg (associated with the change of the dominant hysteresis mechanism), and the simultaneous significant decrease in gate leakage current (which may indicate significant reduction of active defects in the polymer layer). The reversibility of the observed phenomena was also investigated through consecutive thermocycles. Soaking the chip in warm water (60 C) for 3 hours changes the magnitude of the hysteresis loop without changing the direction. The gate leakage current also remains very low. Thus, humidity may play some role in the hysteresis magnitude but not the loop direction, nor does it play any role in the leakage current. In this paper, we will discuss possible explanations of these observations.

Charge pumping is one of the most relied techniques used to quantify interface defects in metal-oxide-semiconductor devices. However, conventional charge pumping is easily hindered by excessive gate leakage currents, which render the technique unsuitable for advanced technology nodes. We demonstrate a new frequency-modulated charge pumping methodology in which we transform the quasi-dc charge pumping measurement into an ac measurement. The ac detection scheme is highly resistant to gate leakage currents and extends the usefulness of charge pumping as a defect monitoring tool for future technologies.

In this paper we report an unexpected improvement in the SiC DMOSFET transistor characteristics after a long temperature treatment at 150 C. The evolution of the device characteristics during a TDDB stress is compared to that after an elevated temperature treatment. The improvement in characteristics after storage at high temperature is believed to be due to instabilities caused by the quality of the SiO2/SiC interface and its large density of defects.

A methodology for the evaluation of ultra-fast interfacial traps, using jitter measurements as a probe, is developed. This methodology is applied to study the effect of PBTI stress on the density of ultra-fast electron traps (with 500 ps to 5 ns characteristic capture/emission times) in a high-k/Si nMOSFET. It is shown, that in spite of an observed increase of timing jitter after PBTI stress, this increase may not be correlated with an increasing density of interface traps. Rather, it is solely caused by a VT shift which simply decreases the output signal amplitude. The results indicate that ultra-fast (presumably interface) traps may not be affected by PBTI stress.

There is significant interest in the development of new dielectrics and new semiconductor/dielectric systems. Of particular interest are new materials for metal oxide field effect transistor systems and new materials for interlayer dielectrics. The electronic defects which limit the performance of these new material systems are largely unknown. Electron paramagnetic resonance (EPR) has unrivaled analytical power for the identification of the physical and chemical nature of trapping centers in semiconductors and insulators (1). However, the sensitivity of conventional EPR is orders of magnitude too low to make measurements in most present day solid state devices. Two electrically detected magnetic resonance (EDMR) techniques, spin dependent recombination (SDR) and spin dependent trap assisted tunneling (SDT) provide the same analytical power as conventional EPR but, in addition, offer a sensitivity many orders of magnitude higher. This enhanced sensitivity allows measurements to be made in essentially “state of the art” device structures and provide several other significant advantages. EDMR can, under some circumstances, provide information about the physical location and energy levels of deep level defects which play important roles in electronic devices. In this presentation, I’ll discuss EDMR results on low-K dielectric constant films (2), on high-K dielectric films on silicon (3), on near interface/interface traps in SiC MOSFET gate dielectrics (4), on defects which play dominating roles in stress induced leakage currents (5) and the negative bias temperature instability (6) in essentially “state of the art” plasma nitrided oxides in silicon based pMOSFETs. I will also show how energy resolved SDT can provide fairly precise measurements of dielectric defect energy levels and show how the SDR response as a function of gate voltage can provide qualitative information about the physical distribution of interface/near interface defects. ACKNOWLDEGEMENTS Work supported by Intel Corporation, U.S. Army Research Laboratory, GE Global Research, and NIST.

We report on a novel electron paramagnetic resonance (EPR) technique that merges electrically detected magnetic resonance (EDMR) with a conventional semiconductor wafer probing station. This union, which we refer to as wafer-level EDMR (WL- EDMR), allows EDMR measurements to be performed on an unaltered, fully processed semiconductor wafer. Our measurements replace the conventional EPR microwave cavity or resonator with a very small non-resonant near-field microwave probe. Bipolar amplification effect, spin dependent charge pumping, and spatially resolved EDMR are demonstrated on various planar 4H-silicon carbide metal-oxide-semiconductor field-effect transistor (4H-SiC MOSFET) structures. 4H-SiC is a wide bandgap semiconductor and the leading polytype for high-temperature and high-power MOSFET applications. These measurements are made via both “rapid scan” frequency-swept EDMR and “slow scan” frequency swept EDMR. The elimination of the resonance cavity and incorporation with a wafer probing station greatly simplifies the EDMR detection scheme and offers promise for widespread EDMR adoption in semiconductor reliability laboratories.

SiC MOSFET, as power device, can be expected to operate with high drain and high gate voltages, possibly leading to hot-carrier effect. However, hot-carrier degradation in a SiC MOSFET is difficult to detect because the as fabricated devices contain high level of defects. We report, for the first time, evidence of hot-carrier effect in 4H-SiC MOSFET. The result suggests that hot hole from impact ionization trapped in the oxide is the cause of the channel hot-carrier effect.

This paper presents a novel experimental setup to perform wafer level TDDB testing. The massively parallel reliability system is capable of testing a total of 3000 probes simultaneously. The system can perform tests at temperatures up to 400 °C for high temperature applications (SiC). We also present TDDB results of SiO2 on SiC showing higher TDDB lifetime and field acceleration compared to SiO2 on Si.

The magnitude of overshoot current during forming has been shown to be a serious issue. Recently we showed that the overshoot duration is equally important in impacting device performance. Shorter duration overshoot in the range of ns yields better performance, suggesting extremely short forming pulse to be desirable. But investigation of such short forming transients is severely limited experimentally due to parasitic. In this study we demonstrate a technique to accurately de-embed these parasitic components yielding accurate forming current transients in the ps range, paving the road to careful study of the forming process.

Our measurements reveal that, similar to much larger power device geometries, hot carrier degradation in ultra-short channel devices involves (1) presumably defect generation-based parametric shifts in threshold voltage/transconductance and (2) an enhancement in series resistance. We show that the series resistance component, which has been seemingly overlooked for ultra-short channel devices, cannot be ignored.

We investigate the validity of using frequency-dependent charge pumping (FD-CP) to determine bulk defect depth distributions. Using simple physical arguments we conclude that: (1) the effective tunneling length to a bulk defect can be very different than its actual physical depth, and (2) only a fraction of detrapping charge may contribute to the CP current (I CP ) resulting in analysis errors. Thus, the relationship between frequency and defect depth is much more complex than what has been previously reported.

In this work, we examine a series resistance extraction technique which yields accurate values from singe nano-scale devices. The series resistance values, derived from this extraction technique, are shown to be sensitive to hot carrier degradation and might possibly serve as new technique to monitor reliability in advanced devices.

There is significant interest in the development of new dielectrics and new semiconductor/dielectric systems. Of particular interest are new materials for metal oxide field effect transistor systems and new materials for interlayer dielectrics. The electronic defects which limit the performance of these new material systems are largely unknown. Electron paramagnetic resonance (EPR) has unrivaled analytical power for the identification of the physical and chemical nature of trapping centers in semiconductors and insulators (1). However, the sensitivity of conventional EPR is orders of magnitude too low to make measurements in most present day solid state devices. Two electrically detected magnetic resonance (EDMR) techniques, spin dependent recombination (SDR) and spin dependent trap assisted tunneling (SDT) provide the same analytical power as conventional EPR but, in addition, offer a sensitivity many orders of magnitude higher. This enhanced sensitivity allows measurements to be made in essentially “state of the art” device structures and provide several other significant advantages. EDMR can, under some circumstances, provide information about the physical location and energy levels of deep level defects which play important roles in electronic devices. In this presentation, I’ll discuss EDMR results on low-K dielectric constant films (2), on high-K dielectric films on silicon (3), on near interface/interface traps in SiC MOSFET gate dielectrics (4), on defects which play dominating roles in stress induced leakage currents (5) and the negative bias temperature instability (6) in essentially “state of the art” plasma nitrided oxides in silicon based pMOSFETs. I will also show how energy resolved SDT can provide fairly precise measurements of dielectric defect energy levels and show how the SDR response as a function of gate voltage can provide qualitative information about the physical distribution of interface/near interface defects. ACKNOWLDEGEMENTS Work supported by Intel Corporation, U.S. Army Research Laboratory, GE Global Research, and NIST.

We develop a simple experimental approach to remove bulk trap contributions from charge pumping data collected on devices which suffer from large amounts of bulk dielectric electron trapping. The approach is more desirable and easier to implement than other simulation/device modeling based approaches. We demonstrate the approach using HfO 2 based MOSFETs. Additionally, we provide an explanation for the smaller than expected bulk trap contribution to charge pumping current.

A new interface defect spectroscopy method based on variable height charge pumping capable of observing the amphoteric nature of Si/SiO 2 interface states in production quality sub-micron devices is demonstrated. It can help to resolve the long standing debate about the true nature of Si/SiO 2 interface states. Additionally, we show that this is a powerful technique for studying other important material systems.

Silicon carbide possesses excellent material properties for high temperature, high frequency and high power applications. Among all the device structures, MOSFET has advantages such as low gate leakage current, easier device control etc., and therefore highly desirable. However, it has long been a common believe that the gate oxide breakdown reliability is a show-stopper, particularly at high temperature where SiC devices are expected to excel. In this paper, we report that the thermally grown gate oxide on 4H-SiC is intrinsically reliable even at temperature as high as 375degC. We further show that even with the current SiC processing technology, devices with 10 cm2 active area can still achieve 100-year lifetime @ E < 2.9 MV/cm and 375degC.