Large area deposition of Si/SiC quantum well films for thermoelectric generator applications

Recent development in thermoelectric conversion, especially in the area of quantum well (QW) thin film materials, have demonstrated the potential to achieve the high efficiency and power density to fabricate future power supplies. In this study, we develop the large area QW films of N-type Si/SiC integrated with P-type B ₄C/B ₉C, which can be used as thermoelectric devices for waste heat recovery. The approach is to fabricate thick large area film stacks (up to 11 μm) deposited by sputter deposition technique on 6 n-type (100) silicon substrates, which might be proven to be a suitable method for potentially manufacturing large area thermoelectric devices in a cost effective manner. These more basic studies are being carried out to better understand variables such as film thickness, deposition rate and other important parameters of these ∼10 nm films. The resulting as deposited and annealed multilayer stacks were characterized in terms of thin film uniformity, thickness, growth rate, composition, and thermoelectric performance, by Spectroreflectometry, atomic force microscopy (AFM), Auger electron spectroscopy (AES), X-ray photoelectron spectroscopy (XPS), X-ray reflectivity (XRR), and electrical measurements. Issues, which could cause film stack degradation, such as interface layer formation, film delamination, and crack formation lowering the device performance will be presented and correlated to device efficiency.