Regensburg 2007 – scientific programme

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HL: Fachverband Halbleiterphysik

HL 15: Preparation and characterization

HL 15.2: Talk

Monday, March 26, 2007, 17:30–17:45, H13

Nano-DLTS based on SCM for spatially resolved electrical defect spectroscopy — •Andre Krtschil, Hartmut Witte, Carsten Baer, Armin Dadgar, and Alois Krost — Institute of Experimental Physics, Otto-von-Guericke-University Magdeburg, PO Box 4120, 39016 Magdeburg, Germany

Conventional techniques for electrical defect characterization like deep level transient spectroscopy (DLTS) suffer from one major problem. They only can provide information on the overall defect content in a macroscopic part of the sample. Otherwise, local defect state characteristics are requested if specific types of structural defects or distinct layers in a device stack should be analyzed.

In this contribution we describe the nano-DLTS technique which overcomes these limitations. Nano-DLTS combines the idea of macroscopic DLTS with the high spatial resolution of the scanning capacitance microscopy approach. Thus, it allows the analysis of local capacitance transients due to an external bias voltage pulse with a spatial resolution of some tens of nanometers. The thermal activation energy of the corresponding defect states can be determined from isothermal nano-DLTS scans at different temperatures.To demonstrate the broad applicability of nano-DLTS, we will show results for different semiconductor layers (silicon, zinc oxide, and gallium nitride) as well as of a more complex GaN-based light emitting diode. In the latter case, the sample is beveled to provide access to inner layers and interfaces during local defect spectroscopy experiments. Furthermore, experimental setup, advantages, and limitations of nano-DLTS will be discussed.