Thermal resistance characteristic of high-power 940nm VCSEL array chip on submount

In the context of globally promoting energy conservation and reducing consumption, reducing the thermal resistance of electronic devices becomes vitally critical. The 940nm Vertical cavity surface emitting laser (VCSEL) is an extremely promising laser, which plays a significant role in various fields, including LiDAR, lighting, military applications, and soon. However, as the power density of single-chip VCSEL array lasers increases, the thermal resistance of the device is rapidly becoming an important limiting factor for its performance. However, the thermal resistance distribution of the VCSEL array module is inexact and not constant. Here, we exhaustively analyzed the thermal resistance characteristics of the 940 nm, 8 W VCSEL array chip on submount (COS) by electrical method combined with structural function algorithm. At 7.50 A, the total apparent thermal resistance of the COS is about 1.19 K/W. Among them, Rchip is nearly0.94 K/W, accounting for as high as 78.99% of the overall thermal resistance. The thermal resistance of the solder layer is approximately 0.07 K/W, accounting for about 5.88%. The thermal resistance of the submount is 0.18K/W, accounting for nearly 15.12%. It shows that the apparent thermal resistance of the VCSEL array chip has become the primary component of the COS, which varies from 1.60 K/W to 0.89 K/W, as the currents change from1.5 Ato9.5A. Accurate thermal resistance analysis is meaningful and crucial, as it helps us understand the core of the problem. The thermal resistance of the chip particularly needs to be emphatically improved in the COS, which will be highly beneficial for energy conservation.