Novel Silicon-Based LED Packaging Module With an Integrated Photosensing Element

Abstract

This letter presents a novel design for a silicon-based light emitting diodes (LEDs) packaging module with an integrated photosensor. The carrier substrate for the LED submount and a photosensitive element are directly fabricated on a silicon wafer, using ion doping and inductively coupled plasma etching, thereby achieving a smart LED packaging module featuring miniaturization, integration and low cost. The subsequent assembly, with a specific heat sink and a shelled optical cap, results in a decrease in thermal effects and improves measurement sensitivity. The typical experiment result shows that the operating temperatures of the LED die and the photosensing element remain below 70 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">°</sup> C and 45 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">°</sup> C, respectively, when the input current to the LED is 0.3 A. The sensitivity of the photosensing module is 8.2 μA/nt for a chip size of 1×1 × 0.15 cm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sup> . The working temperature and photosensitivity of this packaging module can be improved by using a system with high heat dissipation efficiency.