Abstract
Defects in bulk semiconductor crystals are especially damaging to devices, producing catastrophic electrical and optical failures or even limiting lifetime performance and reliability, while driving materials growth costs. New methods for rapid and non-destructive characterization of materials are needed to help overcome limitations in fabrication throughput and application reliability of wide-bandgap power electronics substrates, especially in the development of emerging bulk Gallium Nitride (GaN). Rapid materials characterization methods will help inform the fabrication process parameters impact on materials defects formation, while speeding-up materials development and, ultimately, the deployment of low defect commercially viable and reliable bulk GaN substrates. Here we present an approach for multi-modal defect non-destructive imaging of device-relevant GaN defects with high resolution and high sensitivity. The scanning GaN defects detection system is based on laser pump-and-probe photoluminescence and photothermal measurements that are compared to diode device reliability data from accelerated lifetime testing. We determine that defects detected at optical frequencies reliably predict lifetime performance issues of power electronic devices operating at near DC frequencies[1, 2]. Bulk and epi grown GaN wafer imaging data and test platform device data are correlated to help validate the proposed multi-modal defect detection approach for the reliable detection of defects relevant to the performance of GaN power electronic devices.
This work was performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344. This material is based upon work supported by the U.S. Department of Energy's Office of Energy Efficiency and Renewable Energy (EERE) under the Advanced Manufacturing Office, FY18/FY19 Lab Call.
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