Paper EM2-WeM1
The Influence of Surface Preparation pre-Atomic Layer Deposition of Al₂O₃ on GaN Metal Oxide Semiconductor Capacitors

Wednesday, November 12, 2014, 8:00 am, Room 314

High-κ gate dielectrics have been proposed as a means of producing high performance field effect devices with low gate leakage on GaN-based substrates for low static power consumption, improved transconductance, and higher output power capabilities [1-3]. However, because the surface of GaN may contain defects such as dangling bonds and contaminants [4], understanding the effect of varying surface preparation prior to atomic layer deposition (ALD) of the high-κ gate dielectrics on GaN is of great importance for the advancement of field effect devices. Surface defects and contaminants such as carbon and oxygen may have detrimental effects on optical quality and device performance of GaN based devices. Several methods to improve GaN surface and interface quality have been proposed [4-8]. They include surface cleaning procedures using aqueous (NH₄)₂S, and acid/base treatments such as HCl, HF, NaOH and NH₄OH.

We present a detailed study on the influence of surface preparations pre-atomic layer deposition of Al₂O₃ on GaN metal oxide semiconductor capacitors. The electrical, chemical, and luminescence characteristics of MOS structures prepared on both chemically treated and as-received GaN substrates are reported. Aqueous NH₄OH cleaning shows promise for providing an enhanced starting surface for atomic layer deposition of Al₂O₃ layers on GaN.

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