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

2015 ◽  
Vol 6 ◽  
pp. 2485-2497 ◽  
Author(s):  
Urs Gysin ◽  
Thilo Glatzel ◽  
Thomas Schmölzer ◽  
Adolf Schöner ◽  
Sergey Reshanov ◽  
...  
Keyword(s):  
Silicon Carbide ◽  
Electrostatic Force ◽  
High Vacuum ◽  
Ultra High Vacuum ◽  
Scanning Probe ◽  
Electrostatic Force Microscopy ◽  
Kelvin Probe ◽  
Large Area ◽  
Force Microscopy ◽  
Probe Microscope

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.

Laser cleaning of exfoliated graphene

2012 ◽  
Vol 1455 ◽  
Author(s):  
Oliver Ochedowski ◽  
Benedict Kleine Bußmann ◽  
Marika Schleberger
Keyword(s):  
Local Heating ◽  
High Vacuum ◽  
Ultra High Vacuum ◽  
Ambient Conditions ◽  
Kelvin Probe ◽  
Structural Modifications ◽  
Force Microscopy ◽  
Exfoliated Graphene ◽  
Atomic Force ◽  
P Type

ABSTRACTWe have employed atomic force and Kelvin-Probe force microscopy to study graphene sheets exfoliated on TiO2 under the influence of local heating achieved by laser irradiation. Exfoliation and irradiation took place under ambient conditions, the measurements were performed in ultra high vacuum. We show that after irradiation times of 6 min, an increase of the surface potential is observed which indicates a decrease of p-type carrier concentration. We attribute this effect to the removal of adsorbates like water and oxygen. After irradiation times of 12 min our topography images reveal severe structural modifications of graphene. These resemble the nanocrystallite network which form on graphene/SiO2 but after much longer irradiation times. From our results we propose that short laser heating at moderate powers might offer a way to clean graphene without inducing unwanted structural modifications.

POTENTIAL PROFILE MEASUREMENT OF CARBON NANOTUBE FETs BASED ON THE ELECTROSTATIC FORCE DETECTION

NANO ◽  
2008 ◽  
Vol 03 (01) ◽  
pp. 51-54 ◽  
Author(s):  
YUKI OKIGAWA ◽  
TAKEO UMESAKA ◽  
YUTAKA OHNO ◽  
SHIGERU KISHIMOTO ◽  
TAKASHI MIZUTANI
Keyword(s):  
Carbon Nanotube ◽  
Field Effect ◽  
Potential Distribution ◽  
Field Effect Transistors ◽  
Electrostatic Force ◽  
Electrostatic Force Microscopy ◽  
Profile Measurement ◽  
Kelvin Probe ◽  
Force Detection ◽  
Force Microscopy

We have measured the potential distribution on carbon nanotube (CNT) field-effect transistors (FETs) using electrostatic force microscopy (EFM) and Kelvin probe force microscopy (KFM). Clearer potential profiles were obtained by EFM than by KFM. When the CNT-FET is in the ON state, the EFM image shows uniform potential distribution along the CNT. In contrast, when the CNT-FET is in the OFF state, nonuniform potential image with dark spots are obtained. The dark spots can be attributed to the defects in the CNTs.

Industrial Applications of Scanning Probe Microscopy

1998 ◽  
Vol 4 (S2) ◽  
pp. 522-523
Author(s):  
S. Magonov
Keyword(s):  
Scanning Probe Microscopy ◽  
High Vacuum ◽  
Sample Surface ◽  
Industrial Applications ◽  
Ultra High Vacuum ◽  
Scanning Probe ◽  
Scanning Tunneling ◽  
Tunneling Microscopy ◽  
Probe Microscopy ◽  
Force Microscopy

The evolution of scanning tunneling microscopy (STM) into atomic force microscopy (AFM) have led to a family of scanning probe techniques which are widely applied in fundamental research and in industry. Visualization of the atomic- and molecular-scale structures and the possibility of modifying these structures using a sharp probe were demonstrated with the techniques on many materials. These unique capabilities initiated the further development of AFM and related methods generalized as scanning probe microscopy (SPM). The first STM experiments were performed in the clean conditions of ultra-high vacuum and on well-defined conducting or semi-conducting surfaces. These conditions restrict SPM applications to the real world that requires ambient-condition operation on the samples, many of which are insulators. AFM, which is based on the detection of forces between a tiny cantilever carrying a sharp tip and a sample surface, was introduced to satisfy these requirements. High lateral resolution and unique vertical resolution (angstrom scale) are essential AFM features.

Localized Charge Storage in CeO2/Si(111) By Electrostatic Force Microscopy

1999 ◽  
Vol 584 ◽  
Author(s):  
J. T. Jones ◽  
P. M. Bridger ◽  
O. J. Marsh ◽  
T. C. McGill
Keyword(s):  
Decay Time ◽  
Scanning Probe Microscopy ◽  
Electrostatic Force ◽  
Scanning Probe ◽  
Electrostatic Force Microscopy ◽  
Double Barrier ◽  
Force Microscopy ◽  
Charge Decay ◽  
Initial Charge ◽  
Sample Separation

AbstractIn this report, the local patterning of charge into CeO2/Si structures by scanning probe microscopy is examined. An electrostatic force microscope (EFM) has been used to write and image localized dots of charge on to double barrier CeO2/Si/CeO2/Si(lll) structures. By applying a large tip bias Vtip = 6 – 10 V and reducing the tip to sample separation to z = 3 – 5 nm for write times of t = 30 – 60 s, arrays of charge dots 60 – 250 nm FWHM have been written. The dependence of dot size and total stored charge on various writing parameters such as tip writing bias, tip to sample separation, and write time is examined. The total stored charge is found to be Q = 5 – 200 e per charge dot. These dots of charge are shown to be stable over periods of time greater than 24 hrs, with an initial charge decay time constant of τ ∼ 9.5 hrs followed by a period of much slower decay with τ > 24 hrs. Charge decay time constants are found to be dependent on the thickness of the lower CeO2 tunneling barrier.

Study of Polarization and Relaxation on Pb(Zr,Ti)O3 Thin Films by Scanning Probe Microscopy

2012 ◽  
Vol 463-464 ◽  
pp. 1484-1487
Author(s):  
Jian Shen ◽  
Huai Wu Zhang
Keyword(s):  
Scanning Probe Microscopy ◽  
Negative Charge ◽  
High Vacuum ◽  
Piezoresponse Force Microscopy ◽  
Scanning Probe ◽  
Relaxation Phenomena ◽  
Radio Frequency Magnetron Sputtering ◽  
Kelvin Probe ◽  
Force Microscopy ◽  
Pzt Thin Film

Polycrystalline Pb(Zr0.55T0.45)O3thin film was deposited on Pt/Ti/SiO2Si(100) by radio-frequency-magnetron sputtering method, the writing of charge bits and the polarization relaxation phenomena on the surface of PZT thin film was studied by Kelvin probe force microscopy and Piezoresponse force microscopy, respectively. It is found that the surface potential of the negative charge bits are higher than those of the corresponding positive ones, and the charge accumulates remarkably in high vacuum but relax more quickly. The domain images (contrast) reveal that the polarization magnitude is determined by the orientation of each grain, which is proved by the Ref 14. Taking the polarized area as whole, the relaxation of polarization magnitude (contrast) show that the polarized state in some grain can maintain at leas¬t 105s, but in other grain, the polarization disappear relatively quickly.

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