Light emission from interface traps and bulk defects in SiC MOSFETs

Stahlbush, Robert E.; Macfarlane, P. J.

doi:10.1007/s11664-001-0014-2

Cited by 10 publications

(7 citation statements)

References 7 publications

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“…Lattice images similar to the cross sectional TEM micrographs in Fig. 19 for the 4H-SiC studied here, such stress may result from impurity-induced lattice mismatch between the epilayer and substrate. Such transformation bands may be the result of lattice strain in the epilayer and the subsequent formation of stacking faults.…”

Section: Discussionsupporting

confidence: 56%

Chemically dependent traps and polytypes at Pt/Ti contacts to 4H and 6H–SiC

Tumakha

Brillson

Jessen

et al. 2002

Journal of Vacuum Science &Amp; Technology B: Microelectronics and Nanometer Structures Processing, Measurement, and Phenomena

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Mechanism of ohmic behavior of Al/Ti contacts to p-type 4H-SiC after annealing J. Appl. Phys. 95, 5616 (2004); 10.1063/1.1707215 Schottky barrier height and nitrogen-vacancy-related defects in Ti alloyed Ohmic contacts to n-GaN J. Appl. Phys. 95, 571 (2004); 10.1063/1.1633658Electrical, structural and microstructural characteristics of as-deposited and annealed Pt and Au contacts on chemical-vapor-cleaned GaN thin films We have used low energy electron-excited nanoluminescence ͑LEEN͒ spectroscopy and x-ray photoemission spectroscopy ͑XPS͒ to probe deep level defect states at interfaces of 4H and 6H-SiC with Ti/Pt metallization. These studies aim to identify process conditions under which thermally stable ohmic and Schottky contacts can be obtained on SiC while minimizing the formation of deep level electronic states. Depth-dependent LEEN measurements establish the presence of localized states and their spatial distribution on a nanometer scale. Spectra from the near interface region of 6H-SiC indicate the existence of a SiC polytype with a higher band gap of ϳ3.4 eV. Excitation of the intimate metal-SiC interface reveals a process-dependent discrete state deep within the SiC band gap. XPS measurements reveal consistent differences in the C 1s chemical bonding changes with specific process steps. Analogous chemical treatments of 4H-SiC also produce a lower band gap SiC polytype with ϳ2.5 eV energy extending tens of nanometers beyond the interfaceconfirmed by transmission electron microscopy. This work is the first to show the effect of metalsemiconductor interactions not only on localized states but also on the lattice structure of the semiconductor near the interface.

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Section: Discussionsupporting

confidence: 56%

Chemically dependent traps and polytypes at Pt/Ti contacts to 4H and 6H–SiC

Tumakha

Brillson

Jessen

et al. 2002

Journal of Vacuum Science &Amp; Technology B: Microelectronics and Nanometer Structures Processing, Measurement, and Phenomena

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“…Emission microscopy. First, we employed emission microscopy to visualize the photon emission created during continuous gate switching as observed by Stahlbush et al 37,38 and Macfarlane et al 39 . However, in contrast to their work, we inspected the devices from the reverse side (see Fig.…”

Section: Resultsmentioning

confidence: 99%

“…Others have also performed optical experiments based on laser excitation [30][31][32][33][34][35][36] . In contrast to these well-known approaches, there have been only a few indications that switching a SiC MOSFET electrically from accumulation to inversion or vice versa can lead to light emission via a radiative recombination process [37][38][39][40] . By detecting photons through the polysilicon and the SiO 2 gate dielectric of dedicated test structures, field-effect stimulated radiative recombination was observed in the SiC bulk and via defects at the SiC/SiO 2 interface, whereby the focus was mainly on time-gating the spectral detection and spatially resolving the spread of the recombining charges.…”

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confidence: 99%

Electrically stimulated optical spectroscopy of interface defects in wide-bandgap field-effect transistors

et al. 2023

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Wide-bandgap semiconductors such as silicon carbide, gallium nitride, and diamond are inherently suitable for high power electronics for example in renewable energy applications and electric vehicles. Despite the high interest, the theoretical limit regarding device performance has not yet been reached for these materials. This is often due to charge trapping in defects at the semiconductor-insulator interface. Here we report a one-to-one correlation between electrically stimulated photon emission and the threshold voltage shift obtained from a fully processed commercial 4H-SiC metal-oxide-semiconductor field-effect power transistor. Based on this observation, we demonstrate that the emission spectrum contains valuable information on the energetic position of the charge transition levels of the responsible interface defects. We etch back the transistor from the reverse side in order to obtain optical access to the interface and record the emitted light. Our method opens up point defect characterization in fully processed transistors after device passivation and processing. This will lead to better understanding and improved processes and techniques, which will ultimately push the performance of these devices closer to the theoretical limit.

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“…These darker regions were interpreted as stacking faults that propagate in the basal plane. Stahlbush and MacFarlane [71] observed the time-dependent movement of these 3C inclusions, identified from their 2.3 eV peak energy, in electrically stressed SiC metal-oxide-semiconductor field effect transistors (MOSFETs). They also analysed the emission spectrally, finding a broad emission from 1.5-2.5 eV that they attributed mainly to interface traps.…”

Section: Electrically Stressed Polytype Transformationsmentioning

confidence: 99%

Electron-excited luminescence of SiC surfaces and interfaces

Brillson

Tumakha

Okojie

et al. 2004

J. Phys.: Condens. Matter

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Recent advances in probing the electronic structure of SiC with electron-excited luminescence techniques reveal the presence of localized electronic states near its surfaces and interfaces. These localized states form not only as a result of interface chemical bonding but also due to the formation of new lattice polytypes. Such electronic features are sensitive to the conditions under which the SiC is processed, as well as the application of electrical or mechanical stress. These localized changes on a nanometre scale provide a new perspective to Schottky barrier formation, band alignment, and polytypism in SiC as well as its performance in electronic devices.

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Light emission from interface traps and bulk defects in SiC MOSFETs

Cited by 10 publications

References 7 publications

Chemically dependent traps and polytypes at Pt/Ti contacts to 4H and 6H–SiC

Chemically dependent traps and polytypes at Pt/Ti contacts to 4H and 6H–SiC

Electrically stimulated optical spectroscopy of interface defects in wide-bandgap field-effect transistors

Electron-excited luminescence of SiC surfaces and interfaces

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