The Impact of Interfacial Charge Trapping on the Reproducibility of Measurements of Silicon Carbide MOSFET Device Parameters

Maximilian W Feil,Andreas Huerner,Tibor Grasser,Katja Puschkarsky,Thomas Aichinger,Hans Reisinger,Christian Schleich,Wolfgang Gustin

doi:10.3390/cryst10121143

Maximilian W Feil, Andreas Huerner + Show 6 more

Open Access

https://doi.org/10.3390/cryst10121143

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Abstract

Silicon carbide is an emerging material in the field of wide band gap semiconductor devices. Due to its high critical breakdown field and high thermal conductance, silicon carbide MOSFET devices are predestined for high-power applications. The concentration of defects with short capture and emission time constants is higher than in silicon technologies by orders of magnitude which introduces threshold voltage dynamics in the volt regime even on very short time scales. Measurements are heavily affected by timing of readouts and the applied gate voltage before and during the measurement. As a consequence, device parameter determination is not as reproducible as in the case of silicon technologies. Consequent challenges for engineers and researchers to measure device parameters have to be evaluated. In this study, we show how the threshold voltage of planar and trench silicon carbide MOSFET devices of several manufacturers react on short gate pulses of different lengths and voltages and how they influence the outcome of application-relevant pulsed current-voltage characteristics. Measurements are performed via a feedback loop allowing in-situ tracking of the threshold voltage with a measurement delay time of only 1 μs. Device preconditioning, recently suggested to enable reproducible BTI measurements, is investigated in the context of device parameter determination by varying the voltage and the length of the preconditioning pulse.

Highlights

Silicon carbide (SiC) is a promising wide band gap semiconductor material
The employed commercially available SiC power metal-oxide-semiconductor field-effect transistors (MOSFETs) are from four different vendors
The devices are arbitrarily labeled as A, B, C, and D, whereby A and B have a trench design and C and D are planar MOSFETs

Summary

Introduction

Silicon carbide (SiC) is a promising wide band gap semiconductor material. Especially in power applications, 4H-SiC metal-oxide-semiconductor field-effect transistors (MOSFETs) exhibit advantages over comparable silicon (Si) technologies. Owing to its wide band gap of around 3.26 eV [1], the critical breakdown field of SiC power MOSFETs is around ten times higher than the one of Si devices [2]. SiC devices of the same voltage and on-state resistance class can be made considerably smaller than comparable Si-based devices, leading to reduced device capacitances and enabling higher switching frequencies at lower losses [3,4]. This dramatically reduces volume and weight of inductors, filter capacitors, cooling components and total system costs. More flexible thermal capability, and robustness to hard commutation events make SiC MOSFETs

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