Quantitative electron holography of biased semiconductor devices

Area of Science:

• Materials Science
• Condensed Matter Physics
• Electrical Engineering

Background:

• Semiconductor devices like silicon p-n junctions are fundamental to modern electronics.
• Understanding their electrostatic potential is crucial for device performance and design.
• In situ characterization methods are needed to study these potentials under operating conditions.

Purpose of the Study:

• To measure electrostatic potential profiles across reverse-biased silicon p-n junctions in situ.
• To develop and validate a novel sample geometry for transmission electron microscopy (TEM) based measurements.
• To investigate the influence of sample preparation and electron beam irradiation on surface properties.

Main Methods:

• Utilizing electron holography within a transmission electron microscope (TEM).
• Developing a new sample geometry using focused ion-beam (FIB) milling.
• Performing measurements across varying sample thicknesses and applied bias voltages.

Main Results:

• Successfully obtained electrostatic potential profiles for silicon p-n junctions.
• Established a correlation between holographic contrast and physical/electrical properties.
• Identified the impact of sample surface conditions, influenced by FIB milling and electron irradiation.

Conclusions:

• Electron holography is a viable technique for in situ electrostatic potential measurements in semiconductor devices.
• The novel FIB-milled sample geometry enables accurate characterization.
• Understanding surface effects is critical for interpreting holographic data in TEM.