Electrical properties of AlGaN/GaN HEMTs in stretchable geometries

• Published in: Solid-state electronics Vol. 136; pp. 36 - 42
• Main Authors: Tompkins, R.P., Mahaboob, I., Shahedipour-Sandvik, F., Lazarus, N.
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01-10-2017
• ISSN: 0038-1101; 1879-2405
• DOI: 10.1016/j.sse.2017.06.014

•Fabrication of HEMT devices in both wavy stretchable and conventional geometries.•Device properties are unchanged as a result of changing contact angle.•Device properties are unchanged irrespective of device placement along a sinusoid.
Many biological materials are naturally soft and stretchable, far more so than crystalline semiconductors. Creating systems that can be placed directly on a surface such as human skin has required new approaches in electronic device design and materials, a field known as stretchable electronics. One common method for fabricating a highly brittle semiconductor device able to survive tens of percent strain is to incorporate stress relief structures (‘waves’). Although the mechanical advantages of this approach are well known, the effects on the electrical behavior of a device such as a transistor compared to a more traditional geometry have not been studied. Here, AlGaN/GaN high electron mobility transistors (HEMTs) grown on rigid sapphire substrates were fabricated in a common wavy geometry, a sinusoid, with dimensions similar to those used in stretchable electronics. The study analyzes control parameters available to the designer including gate location along the sinusoid, angle the source-drain contacts make with the gate, as well as variation of the gate length at the peak of the sinusoid. Common electrical parameters such as saturation current density, threshold voltage, and transconductance were compared between the sinusoidal and conventional straight geometries and results found to fall to within experimental uncertainty, suggesting shifting to a stretchable geometry is possible without appreciably degrading semiconductor device performance.