Influence of transparent surface layer on effective thermoreflectance coefficient of typical stacked electronic structures

The investigation of the influence of a transparent passivation layer on the effective thermoreflectance coefficient of metallic and semiconductor materials is carried out for two materials and two types of passivation layers. This investigation is targeted at determining the effective Ctr for composite structures typically found in microelectronic devices; namely, transparent passivation layers covering either semiconductor or metallic materials. The layer of poly-Si or gold is deposited on a Si substrate and covered with a layer of either SiO₂ or Si₃N₄. To study the light interference effect on the C_TR value of poly-Si and gold films, the thickness of the passivation layer is varied in the range that envelopes the test wavelength of the light source. The experimental values of the effective C_TR are obtained with the intent of correlating them with the intrinsic values of C_TR for the materials under study (poly-Si and gold) and the thickness and/or material of the transparent passivation layers (SiO₂ or Si₃N₄).