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A master's thesis from Aalborg University
Book cover


Design and characterisation of a shear-based direct-write deposition system for GaInSn

Author

Term

4. semester

Publication year

2026

Pages

45

Abstract

Silicon carbide (SiC) power chips can last longer and operate at higher temperatures if their electrical interconnects are more robust. Gallium-based liquid metals are promising because they remain fluid at room temperature yet conduct electricity like metals. This thesis designed, built, and characterized a shear-driven direct-write system (a printing approach that uses shear to deposit material) for Galinstan, a gallium–indium–tin alloy. The setup used 4-axis motion, adapted an existing framework by Boley et al., and was tested by writing lines on three substrates: copper (Cu), gold (Au), and tantalum (Ta). Galinstan lines were deposited successfully on all three materials. The study also identified limitations, including issues related to using a stainless steel nozzle and priming that expelled about 3.8 times the nozzle’s internal volume before stable flow. The Boley framework transferred well to this application. Overall, the approach was shown to be feasible, and key system limitations were identified to guide future improvements.

Siliciumcarbid (SiC)-baserede chips i effektelektronik kan få længere levetid og tåle højere temperaturer, hvis deres elektriske forbindelser kan holde til belastningen. Gallium-baserede flydende metaller er lovende, fordi de er flydende ved stuetemperatur og leder strøm som metaller. I denne afhandling blev der derfor designet, bygget og karakteriseret et shear-drevet direct-write system (en printmetode, hvor forskydning bruges til at lægge materiale ned) til Galinstan, en gallium–indium–tin legering. Systemet havde 4-aksers bevægelse, tog udgangspunkt i et tidligere rammeværk af Boley m.fl., og blev testet ved at skrive linjer på tre substrater: kobber (Cu), guld (Au) og tantal (Ta). Deponering af Galinstan-linjer lykkedes på alle tre materialer. Under testen blev der identificeret begrænsninger, herunder udfordringer ved brug af en dyse i rustfrit stål samt priming, der krævede udskillelse af cirka 3,8 gange dysevolumenet, før stabil flow opstod. Rammeværket fra Boley viste god overførbarhed. Samlet set blev metoden vurderet som gennemførlig, og de væsentligste systembegrænsninger blev kortlagt til fremtidige forbedringer.

[This apstract has been rewritten with the help of AI based on the project's original abstract]