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Master thesis: Electrical and structural characterization of yttrium aluminum nitride (YAlN).

Master Topic:

Interest in transition metal nitrides (MxX1-xN) has increased in recent decades. MxX1-xN exhibit outstanding properties such as high hardness, high temperature stability and mechanical strength. These properties enable improvements in a wide range of technological applications. The most prominent ternary transition metal nitride is scandium aluminum nitride (ScAlN) due to its outstanding piezoelectric properties and the appearance of the ferroelectric effect. This motivates the exploration of other MxX1-xN such as CrAlN and YAlN. According to simulations, these are the most promising candidates in terms of piezoelectric and spontaneous polarization application. Similar to ScN, YN and CrN are also present in the cubic rock-salt structure, so there must be a phase transition from hexagonal AlN with increasing x. This type of phase transition is still relatively unexplored and opens up a wide range of applications in electronic devices. Since chromium compounds are generally toxic, YScN is the next material of scientific interest to investigate the material properties and phase transition depending on the yttrium content.

 

 Metal Nitride

Details:

  • Usual duration: 6 months
  • Start: immediately
  • Prior Knowledge:
    • Fundamentals in solid state and semiconductor physics as well as crystallography are helpful
    • Studies in Sustainable Systems Engineering, Microsystems Engineering, Physics, Chemistry, Materials Science, or a comparable scientific-technical subject
  • In addition to the master thesis, a HiWi position can be offered to support the scientific projects of the chair up to max. 40h/month

Activity Description:

  • Growth of YAlN thin films on different substrates (Si, sapphire, ...) by DC magnetron sputtering epitaxy in clean room.

  • Structural and electrical characterization of the prepared thin films

  • Determination of lattice parameters and other structural properties at temperatures up to 900 °C by X-ray diffraction (XRD)

  • Determination of the thermal expansion coefficient α and the layer stress σ

  • Measurement of temperature-dependent electrical properties

 

We expect:

  • Interest in growth processes of novel materials
  • Pleasure in participating in a team of researchers

 

We offer:

  • Introduction to sputtering of epitaxial semiconductor nitride thin films

  • Thorough introduction to the state of the art of research on III-V semiconductors

  • Work as a student assistant at your own work station at INATECH

  • Training in characterization techniques such as atomic force microscopy (AFM), X-ray diffraction (XRD), electrical measurements (CV, IV), UV-VIS, etc.

 

Kontakt

Prof. Dr. Dr. Oliver Ambacher

INATECH - Leistungselektronik
Emmy-Noether-Straße 2
79110 Freiburg im Breisgau

oliver.ambacher@inatech.uni-freiburg.de