Development of power semiconductors by quantitative nanoscale dopant imaging

Bartolf, Holger; Gysin, Urs; Rossmann, H.; Bubendorf, Alexander; Glatzel, Thilo; Jung, Thomas A.; Meyer, Ernst; Zimmermann, Martín; Reshanov, Sergey A.; Schöner, Adolf

doi:10.1109/ispsd.2015.7123444

Cited by 2 publications

(3 citation statements)

References 18 publications

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“…1 and Eq. 3 [ 57 ]. A much longer decay of the surface potential was also observed by M. Gao et al in locally resolved secondary electron emission measurements across a SiC p / n-junction [ 44 ].…”

Section: Resultsmentioning

confidence: 99%

“…An alternative approach for such devices is the so-called junction barrier Schottky (JBS) rectifier-architecture, where highly doped p + -regions are embedded into the active device area to shield the Schottky contact from high electric fields and to handle surge-current events at the same time [ 59 – 60 ]. The implantation of dopants as well as the electronic properties of these embedded shields is a key property and needs sophisticated characterization [ 57 ].…”

Section: Resultsmentioning

confidence: 99%

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Large area scanning probe microscope in ultra-high vacuum demonstrated for electrostatic force measurements on high-voltage devices

Gysin

Glatzel

Schmölzer

et al. 2015

Beilstein J. Nanotechnol.

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Summary Background: The resolution in electrostatic force microscopy (EFM), a descendant of atomic force microscopy (AFM), has reached nanometre dimensions, necessary to investigate integrated circuits in modern electronic devices. However, the characterization of conducting or semiconducting power devices with EFM methods requires an accurate and reliable technique from the nanometre up to the micrometre scale. For high force sensitivity it is indispensable to operate the microscope under high to ultra-high vacuum (UHV) conditions to suppress viscous damping of the sensor. Furthermore, UHV environment allows for the analysis of clean surfaces under controlled environmental conditions. Because of these requirements we built a large area scanning probe microscope operating under UHV conditions at room temperature allowing to perform various electrical measurements, such as Kelvin probe force microscopy, scanning capacitance force microscopy, scanning spreading resistance microscopy, and also electrostatic force microscopy at higher harmonics. The instrument incorporates beside a standard beam deflection detection system a closed loop scanner with a scan range of 100 μm in lateral and 25 μm in vertical direction as well as an additional fibre optics. This enables the illumination of the tip–sample interface for optically excited measurements such as local surface photo voltage detection. Results: We present Kelvin probe force microscopy (KPFM) measurements before and after sputtering of a copper alloy with chromium grains used as electrical contact surface in ultra-high power switches. In addition, we discuss KPFM measurements on cross sections of cleaved silicon carbide structures: a calibration layer sample and a power rectifier. To demonstrate the benefit of surface photo voltage measurements, we analysed the contact potential difference of a silicon carbide p/n-junction under illumination.

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Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Large area scanning probe microscope in ultra-high vacuum demonstrated for electrostatic force measurements on high-voltage devices

Gysin

Glatzel

Schmölzer

et al. 2015

Beilstein J. Nanotechnol.

View full text Add to dashboard Cite

show abstract

“…With the enhancement of device integration and the reduction in feature size to < 3 nm, there is an urgent need for a doping profiling technique with high resolution and high sensitivity. 3,4 Currently, capacitancevoltage profiling, 5,6 secondary ion mass spectrometry, 7,8 spreading resistance profiling, 9,10 scanning tunnelling microscopy 11 and electron holography 12 are often used for doping profiling. However, these techniques are more or less suffer from low spatial resolution, low accuracy, poor limit of detection, low throughput, time consuming, or high cost.…”

Section: Introductionmentioning

confidence: 99%

Optimized dopant imaging for GaN by a scanning electron microscopy

Ban

Yuan

Huang

2023

Journal of Microscopy

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Two-dimensional dopant profiling is vital for the modelling, design, diagnosis and performance improvement of semiconductor devices and related research and development. Scanning electron microscopy (SEM) has shown great potential for dopant profiling. In this study, the effects of secondary electron (SE) detectors and imaging parameters on the contrast imaging of multilayered p-n and p-i junction GaN specimens via SEM were studied to enable dopant profiling. The doping contrast of the image captured by the in-lens detector was superior to that of the image captured by the side-attached Everhart-Thornley detector at lower acceleration voltages (V acc ) and small working distances (WD). Furthermore, the doping contrast levels of the in-lens detector-obtained image under different combinations of V acc and WD were studied, and the underlying mechanism was explored according to local external fields and the refraction effect. The difference in the angular distributions of SEs emitted from different regions, the response of the three types of SEs to detectors, and the solid angles of detectors toward the specimen surface considerably influenced the results. This systematic study will enable the full exploitation of SEM for accurate dopant profiling, improve the analysis of the doping contrast mechanism, and further improve doping contrast for semiconductors.

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Development of power semiconductors by quantitative nanoscale dopant imaging

Cited by 2 publications

References 18 publications

Large area scanning probe microscope in ultra-high vacuum demonstrated for electrostatic force measurements on high-voltage devices

Large area scanning probe microscope in ultra-high vacuum demonstrated for electrostatic force measurements on high-voltage devices

Optimized dopant imaging for GaN by a scanning electron microscopy

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