Simultaneous Measurement of Thermal Conductivity and Volumetric Heat Capacity of Thermal Interface Materials Using Thermoreflectance.

Thermal interface materials are crucial to minimize the thermal resistance between a semiconductor device and a heat sink, especially for high-power electronic devices, which are susceptible to self-heating-induced failures. The effectiveness of these interface materials depends on their low thermal contact resistance coupled with high thermal conductivity. Various characterization techniques are used to determine the thermal properties of the thermal interface materials.

Characterizing electric fields in semiconductor devices: effect of second-harmonic light interference.

Characterizing electric fields in semiconductor devices using electric field-induced second-harmonic generation (EFISHG) has opened new opportunities for an advanced device design. However, this new technique still has challenges due to the interference between background second-harmonic generation (SHG) and EFISHG generated light. We demonstrate that interference effects can effectively be eliminated during EFISHG measurements by focusing the laser from the transparent substrate side of a GaN PN diode, enabling straightforward quantitative electric field analysis, in contrast to PN junction interface side measurements.

Thermal Characterization of Metal-Diamond Composite Heat Spreaders Using Low-Frequency-Domain Thermoreflectance.

High thermal conductivity and an appropriate coefficient of thermal expansion are the key features of a perfect heat spreader for electronic device packaging, especially for applications with increased power density and the increasing demand for higher reliability and semiconductor device performance. For the past decade, metal-diamond composites have been thoroughly studied as a heat spreader, thanks to their high thermal conductivities and tailored coefficients of thermal expansion. While existing thermal characterization methods are good for quality control purposes, a more accurate method is needed to determine detailed thermal properties of these composite materials, especially if clad with metal.

In situ Thermoreflectance Characterization of Thermal Resistance in Multilayer Electronics Packaging.

High-performance, high-reliability microelectronic devices are essential for many applications. Thermal management is required to ensure that the temperature of semiconductor devices remains in a safe operating range. Advanced materials, such as silver-sintered die attach (the bond layer between the semiconductor die and the heat sink) and metal-diamond composite heat sinks, are being developed for this purpose.

Crystalline Interlayers for Reducing the Effective Thermal Boundary Resistance in GaN-on-Diamond.

Integrating diamond with GaN high electron mobility transistors (HEMTs) improves thermal management, ultimately increasing the reliability and performance of high-power high-frequency radio frequency amplifiers. Conventionally, an amorphous interlayer is used before growing polycrystalline diamond onto GaN in these devices. This layer contributes significantly to the effective thermal boundary resistance (TBR) between the GaN HEMT and the diamond, reducing the benefit of the diamond heat spreader.

Thick, Adherent Diamond Films on AlN with Low Thermal Barrier Resistance.

The growth of >100-μm-thick diamond layers adherent on aluminum nitride with low thermal boundary resistance between diamond and AlN is presented in this work. The thermal barrier resistance was found to be in the range of 16 m·K/GW, which is a large improvement on the current state-of-the-art. While thick films failed to adhere on untreated AlN films, AlN films treated with hydrogen/nitrogen plasma retained the thick diamond layers.