What Determines the Lifetime of a Laser Diode Module?

Semiconductor lasers have the advantages of wide output wavelength range, simple structure and easy integration, and are widely used in medical, sensing, optical communication, military and aerospace fields. So what can cause damage to the Laser diode module? There may be the following reasons:

The failure or damage mode of the Laser diode module is mainly manifested in the absence of output light intensity during operation, or the failure of the output optical power degradation under a constant driving current. When the output power degrades to a specific threshold, the laser will fail.

The Reliability Research and Analysis Center is the earliest authoritative organization in China specializing in electronic components and various electronic product failure analysis technology research and technical services. In the failure analysis of semiconductor lasers, it is concluded that the main failure mechanisms of semiconductor lasers include High operating temperature, electrode degradation, ohmic contact, cavity surface degradation, environmental pollution and other factors. The failure mechanism introduction and related cases are shown below.

Typical lifetime of laser diode modules are 10,000 to 25,000 hours. If the laser diode temperature rises beyond the maximum operating temperature the long-term performance may degrade significantly, up to and including complete failure. If the laser diode’s operating temperature is reduced by about 10 degrees, the lifetime will statistically double.

Laser module lifetime can be extended significantly by maintaining the case temperature at the low end of the operating temperature range. Heat sinks are recommended and must be used if the laser is operating constantly. Operating the laser modules at the low end of the recommended voltage range will also help to extend the lifetime of the laser.

2) Electrode degradation

Electrode degradation usually occurs at the interface between the metal and the semiconductor material. Due to the diffusion of the solder material into the semiconductor to form a defect structure, under the action of a large current, the heat accumulation at the defect position will eventually burn the nearby metallization layer.

3) Ohmic contact

If there is a large thermal mismatch between the chip and the solder, the laser will cause stress concentration at the material interface during welding or work, which will cause solder cracking or chip cracking. In addition, when welding the laser, there is a welding gap between the chip and the solder that will cause the laser to fail, and the overflow of the solder during welding will also easily lead to a short circuit at the PN junction.

4) Cavity surface degradation

Cavity surface degradation is a failure mode that distinguishes lasers from other microelectronic devices. Since the material of the active region of the laser contains Al or In elements, and when the uniformity or consistency of the chip design and manufacturing process is poor, the Al and In elements will melt or recrystallize under high-power operation, resulting in impurities or Defects, so that the temperature of this region continues to rise, and the current density of the end face continues to increase, resulting in a further rise in the temperature of this region, which eventually leads to catastrophic optical damage.

5) Environmental pollution

Environmental pollution is an external factor that leads to the failure of semiconductor lasers. The main reason is that particles such as dust, water vapor, and ion pollutants enter the interior of the semiconductor laser and attach to the surface of the chip to cause a short circuit or open circuit, which eventually leads to device failure.

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