Effect of AlGaN Barrier Thickness on Trapping Characteristics in AlGaN/GaN Heterostructures

  • Apurba ChakrabortyEmail author
  • Saptarsi Ghosh
  • Subhashis Das
  • Ankush Bag
  • Dhrubes Biswas
Conference paper
Part of the Springer Proceedings in Physics book series (SPPHY, volume 215)


Aluminum Gallium Nitride (AlGaN) barrier thickness dependent trapping characteristic of AlGaN/GaN heterostructure is investigated by frequency dependent conductance measurement. The conductance measurement in depletion region biases (−4.8 to −3.2 V) shows that the \( {\text{Al}}_{0.3} {\text{Ga}}_{0.7} {\text{N}}\left( {18\;{\text{nm}}} \right)/{\text{GaN}} \) structure suffers from both the surface (metal/AlGaN interface of gate region) and interface (AlGaN/GaN interface of channel region) trapping states, whereas the \( {\text{Al}}_{0.3} {\text{Ga}}_{0.7} {\text{N}} \left( { 25\;{\text{nm}}} \right)/{\text{GaN}} \) structure with thicker AlGaN barrier (25 nm) layer suffers from only interface trap energy states in the depletion bias region (−6.0 to −4.2 V). The calculated surface trap time constants (~2 μs) are found to be very less in \( {\text{Al}}_{0.3} {\text{Ga}}_{0.7} {\text{N}}\left( {18\;{\text{nm}}} \right)/{\text{GaN}} \) structure. This lower time constant is correlated to the electric field induced tunneling process for de-trapping of surface trap states.



Authors gratefully acknowledge project titled “ENS” sponsored by Dept. of Electronics and Information Technology (DeitY), Govt of India for providing fabrication and characterization facility.


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© Springer Nature Switzerland AG 2019

Authors and Affiliations

  • Apurba Chakraborty
    • 1
    Email author
  • Saptarsi Ghosh
    • 2
  • Subhashis Das
    • 3
  • Ankush Bag
    • 3
  • Dhrubes Biswas
    • 4
  1. 1.Department of ECENIT AgartalaBarjala, JiraniaIndia
  2. 2.SSPL, DRDONew DelhiIndia
  3. 3.IIT MandiMandiIndia
  4. 4.E&ECEIIT KharagpurKharagpurIndia

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