Current spreading and thermal effects in blue LED dice

We have applied simulations to study current the spreading and heat transfer in blue III‐nitride light‐emitting diodes (LEDs) with the focus on self‐heating and its effect on the device characteristics. A conventional planar design of an LED die is considered for the heat sink through a sapphire substrate. The computations predict a great current crowding at the contact electrode edges, resulting in a non‐uniform temperature distribution over the die. The thermal effect on the current‐voltage characteristic, output optical power, and series resistance of the diode is analyzed and the theoretical predictions are compared with available observations. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)