Berlin 2015 – scientific programme
Parts | Days | Selection | Search | Updates | Downloads | Help
HL: Fachverband Halbleiterphysik
HL 96: Poster III C (III-V Semiconductors incl. Nitrides)
HL 96.21: Poster
Thursday, March 19, 2015, 14:00–20:00, Poster B
Optimization of Ohmic contacts of GaN HEMTs with AlN spacer — •Teresa Baur1,2, Sebastian Mansfeld2, Helmut Jung2, Manfred Madel2, Hervé Blanck2, Jan Grünenpütt2, Bernd Schauwecker2, and Klaus Thonke1 — 1Institute of Quantum Matter / Semiconductor Physics Group, Ulm University, 89081 Ulm, Germany — 2United Monolithic Semiconductors GmbH, 89081 Ulm, Germany
As a promising candidate for future microwave and millimeterwave power devices, AlGaN/GaN high-electron mobility transistors (HEMTs) have attracted much research interest. In order to realize the full potential of AlGaN/GaN HEMTs as high-power, high-frequency, and high-temperature devices Ohmic contacts with low specific resistance are essential. The electron mobility in the two-dimensional electron gas (2DEG) can be increased by inserting a thin Aluminum Nitride spacer at the AlGaN-GaN interface, which reduces alloy scattering. This AlN spacer lowers the sheet resistance, but also typically leads to undesirable higher ohmic contact resistance.
A possible way to circumvent this disadvantage is to reduce the distance between the contact and the 2DEG by creating a recess prior to the metallization step. Electrical data extracted from the Transmission Line Measurement (TLM) confirm this theory.
In order to better understand the physical conduction mechanisms at the metal/semiconductor interface, temperature-dependent I(V) measurements were undertaken for different sample configurations.