Improved quality of sputtered AlN and AlScN layers for BAW RF filters

Master Thesis

In the network of science and industry, Silicon Austria Labs (SAL) offers re­search in four pionee­ring divi­sions: Sensor Systems, RF Systems, Power Elec­tro­nics and System Inte­gra­tion. SAL – a great place to re­search. 

Aim of the thesis

Recent years have seen increasing mobile wireless traffic resulting in increasing number of RF filters in smartphones.  RF filters based on Bulk Acoustic Waves (BAW) devices could play a significant role in the 5G if the devices success to reach the higher frequencies (between 3.5 GHz and 6 GHz) required to reach higher data rates. For future high frequency BAW devices, the layer of piezoelectric material (AlN, AlScN) must be considerably thinner than currently achievable.

The objective of this thesis is to fabricate, by sputtering, high quality AlN and AlScN layers with thickness < 1µm on Si substrates. To achieve this goal the candidate will introduce and optimize the quality different intermediate layers (electrodes, buffer layers). Based on the results, the successful candidate will have the opportunity to propose a new layer stack for the future generation of BAW devices.

In particular, the candidate will:

  • Gain fundamental understanding of sputtered thin films layers growths principles and influence parameters
  • Experimentally characterize thin films (mechanical profilometer, XRD, SEM, FTIR)
  • Apply the theoretical and experimental knowledge acquired during the first part of the thesis to elaborate new concepts for BAW layer stack

Profile / Requirements

  • Master student in material science, physics, semiconductor technologies, microsystem technology or similar fields
  • Experience in cleanroom would be appreciated
  • Experience with experimental data processing software (e.g. Matlab, Mathematica, Python,…) is also beneficial.
  • Autonomous, well orga­nized and enjoy working in a dynamic and multi­cul­tural team.
  • Oral and written commu­ni­ca­tion skills in English.

    We offer

    • State-of-the-art laboratories and equipment, including the opportunity to work in a cleanroom environment.
    • An international scientific environment and contacts with our industrial network
    • Opportunity to work on a hot topic with industrial collaborations


    Start Date / Duration / Contract

    • Start date (planned): February - March 2019
    • Duration (planned): 6 Months
    • Contract: 1380€/month
    • Place: Silicon Austria Labs, Villach, Austria