High mobility Si0.15Ge0.85 growth by using the molten target sputtering (MTS) within heteroepitaxy framework

Abstract

High-speed SiGe film is promising use in photonics and electronics technologies continue to replace Si-based devices. High mobility Si 0.15 Ge 0.85 film on sapphire was grown at 890 °C substrate temperature by using a conventional magnetron sputtering system within the heteroepitaxy framework. 890 °C substrate temperate is impractical for commercial device manufacturing due to long thermal soak, loading time, and costly process. To leverage the practical SiGe device applications, the Molten Target Sputtering (MTS) techniques is developed. The MTS is an economic and robust process from high flux density and liquid-state of molecules benefits. At 500 °C, the lowest substrate temperature, high mobility Si 0.15 Ge 0.85 film with continues morphology and 99.7% majority-orientation were grown by using the MTS. The hall electron mobilities of the Si 0.15 Ge 0.85 grown at 500 °C are 456 cm 2 V −1 s −1 and 123.9 cm 2 V −1 s −1 at 5.59 × 10 18 cm 3 and 3.5 × 10 20 cm 3 carrier concentration at 22.38 °C, respectively. The values are 550% higher hall electron mobilities than that of Si at equivalent carrier concentration and temperatures. We envision that the MTS is beneficial for the heteroepitaxy framework film growth that requires high substrate temperature to overcome the large lattice parameter mismatch between film and substrate.

Mass-resolved spectrometry of ion flux from hot-target reactive HiPIMS discharge with Si target

“…Experiments were carried out for thermally insulated Si target. These material is known for its comparatively high vapor pressure and the possibility of sustaining magnetron discharge in target vapor [1,2]. The HiPIMS discharge was operated in O2/Ar mixtures.…”

Hot target magnetron sputtering process: Effect of infrared radiation on the deposition of titanium and titanium oxide thin films

“…This can even lead to a liquid target surface. Performing sputtering with a high target temperature leads to an increase of deposition rate [15][16][17][18][19][20][21][22][23][24][25][26], improves crystalline quality (especially oxides) and influences texture [19][20][21][22][23][24][25][26] without any-annealing treatments, modifies stoichiometry, especially for thin film containing volatile/labile elements [27], enhances reactive sputtering stability by reducing hysteresis loop [28], enhances thin film hardness, decreases average surface roughness [24,25], allows heteroepitaxy framework film growth that usually requires high substrate temperature to overcome large lattice parameter mismatch between film and substrate [29]. This could also help igniting/sustaining magnetron discharge during the sputtering of a ferromagnetic target by reaching its target paramagnetic state above the Curie temperature [30][31][32].…”