Investigation of Reverse Leakage Characteristics of InGaN/GaN Light-Emitting Diodes on Silicon

Abstract

We investigate the reverse leakage characteristics of InGaN/GaN multiple-quantum-well light-emitting diodes (LEDs) grown on Si (111) substrate by metal-organic chemical vapor deposition. The reverse leakage characteristics of InGaN/GaN LED on silicon are measured as low as ~10 nA at -5 V and -10 μA at -15 V. Temperature-dependent current-voltage ( <i xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">I</i> - <i xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">V</i> ) measurements of LED devices reveal that the reverse leakage current mechanism is mainly attributed to the field-enhanced thermionic emission, also known as Poole-Frenkel emission, of carriers from deep centers within the space charge region up to ~ -18 V. The analysis of <i xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">T</i> - <i xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">I</i> - <i xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">V</i> curve yields the calculation of the coefficient of the Poole-Frenkel effect (1.12 × 10 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-4</sup> eV·V <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-1/2</sup> ·cm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">1/2</sup> ) and activation energies of carriers (~214 meV at -5 V). With further increase of reverse bias, up to -40 V, LED devices exhibit the onset of space-charge-limited leakage current mechanism without any local breakdown.