Influence of Process Technology on DC-Performance of GaN-Based HFETs

Autor: Zahia Bougrioua, J. Graul, F. Fedler, H. Klausing, O.K. Semchinova, T. Rotter, M. Marso, D. Mistele, H. Roll, Ingrid Moerman
Rok vydání: 2002
Předmět:
Zdroj: physica status solidi (a). 194:452-455
ISSN: 1521-396X
0031-8965
DOI: 10.1002/1521-396x(200212)194:2<452::aid-pssa452>3.0.co;2-n
Popis: This work reports on the influence of the surface and the gate length on the performance of AlGaN/ GaN based Hetero Field Effect Transistors (HFETs). Differently NH 4 S x treated surfaces result in variation of the drain current I Dmax of more then 100%. Gate recessing by photoelectrochemical treatment changes the threshold voltage V th but affects the drain current little. Next, the reduction of the gate length increases the I Dmax further by more than 60%. The I Dmax values for the transistors are 350 mA mm -1 for the NH 4 S x -treated, 850 mA for the untreated, and 1.43 A mm -1 for the one with a 0.2 μm gate length. The corresponding transconductances g m are 66, 150, and 280 mS mm -1 , respectively. Surface analysis with Auger Electron Spectroscopy (AES) and contact characterization (TLM) reveals, that the NH 4 S x treatment removes the native oxide and increases the contact resistance as well. Therefore we attribute the increase of I Dmax and g m mainly to a beneficial behavior of gallium-oxide at the surface on the sheet carrier density n s of the 2DEG at the heterointerface.
Databáze: OpenAIRE
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