Thermal stability of SiGe films on an ultra thin Ge buffer layer on Si grown at low temperature

Chen, Chengzhao; Zhou, Zhiwen; Chen, Yanghua; Cheng, Li; Lai, Hongkai; Chen, Songyan

doi:10.1016/j.apsusc.2010.04.076

Cited by 8 publications

(2 citation statements)

References 23 publications

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“…However, as the germanium thickness increased to 2.0 µm, the surface roughness was similar to that of 1.2 µm. The roughening of Si 0.2 Ge 0.8 /Ge stack layers grown on thin Ge buffer layers was mainly due to the formation of misfit dislocations with crosshatch undulation [ 33 ], surface diffusion and intermixing of Ge and Si at high temperature (650 °C) during the growth of the Ge buffer layer [ 34 ]. As can be seen from the analysis above, the thick Ge buffer layer reduced the surface roughness of Si 0.2 Ge 0.8 /Ge stack layers.…”

Section: Resultsmentioning

confidence: 99%

Strained Si0.2Ge0.8/Ge multilayer Stacks Epitaxially Grown on a Low-/High-Temperature Ge Buffer Layer and Selective Wet-Etching of Germanium

et al. 2020

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With the development of new designs and materials for nano-scale transistors, vertical Gate-All-Around Field Effect Transistors (vGAAFETs) with germanium as channel materials have emerged as excellent choices. The driving forces for this choice are the full control of the short channel effect and the high carrier mobility in the channel region. In this work, a novel process to form the structure for a VGAA transistor with a Ge channel is presented. The structure consists of multilayers of Si0.2Ge0.8/Ge grown on a Ge buffer layer grown by the reduced pressure chemical vapor deposition technique. The Ge buffer layer growth consists of low-temperature growth at 400 °C and high-temperature growth at 650 °C. The impact of the epitaxial quality of the Ge buffer on the defect density in the Si0.2Ge0.8/Ge stack has been studied. In this part, different thicknesses (0.6, 1.2 and 2.0 µm) of the Ge buffer on the quality of the Si0.2Ge0.8/Ge stack structure have been investigated. The thicker Ge buffer layer can improve surface roughness. A high-quality and atomically smooth surface with RMS 0.73 nm of the Si0.2Ge0.8/Ge stack structure can be successfully realized on the 1.2 µm Ge buffer layer. After the epitaxy step, the multilayer is vertically dry-etched to form a fin where the Ge channel is selectively released to SiGe by using wet-etching in HNO3 and H2O2 solution at room temperature. It has been found that the solution concentration has a great effect on the etch rate. The relative etching depth of Ge is linearly dependent on the etching time in H2O2 solution. The results of this study emphasize the selective etching of germanium and provide the experimental basis for the release of germanium channels in the future.

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Section: Resultsmentioning

confidence: 99%

Strained Si0.2Ge0.8/Ge multilayer Stacks Epitaxially Grown on a Low-/High-Temperature Ge Buffer Layer and Selective Wet-Etching of Germanium

et al. 2020

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“…Getting good quality films with high degree of strain relaxation and low dislocation density is a challenge. The effect of annealing on SiGe thin films grown using an ultrahigh-vacuum chemical vapor deposition (UHVCVD) has been reported elsewhere [6][7][8][9][10]. However there are not many studies on PECVD grown SiGe films.…”

Section: Introductionmentioning

confidence: 99%