A Si0.7Ge0.3 strained-layer etch stop for the generation of thin layer undoped silicon

Abstract

The use of a Si0.7Ge0.3 strained layer as an etch stop in silicon-based materials is reported. The etch rates were characterized through silicon and a 60 nm Si0.7Ge0.3 strained layer. The etch rate through undoped silicon was 17–20 nm/min, while the etch rate through the Si0.7Ge0.3 layer was 1 nm/min. After annealing the wafer to 850 °C for 30 min, transmission electron microscopy was used to show that strain in the alloy layer was only partially relieved, and that generated misfit dislocations were confined to the strained Si0.7Ge0.3 layer. The etch rate through the strained layer increased to 1.7 nm/min after this treatment, and was still perfectly functional as an etch stop.

Compliant substrates: A comparative study of the relaxation mechanisms of strained films bonded to high and low viscosity oxides

“…The film separation by hydrogen implantation (Smart-Cut) 9 and bond and etch back SOI (BESOI) 10 fabrication techniques have been successfully joined to produce bonded Si films less than 5 nm thick and of excellent uniformity. The film separation by hydrogen implantation (Smart-Cut) 9 and bond and etch back SOI (BESOI) 10 fabrication techniques have been successfully joined to produce bonded Si films less than 5 nm thick and of excellent uniformity.…”

Selective Chemical Wet Etching of Si0.8Ge0.2/Si Multilayer

“…Two important parameters of chemical selective wet etching have also been checked: ageing time of etching solution and structure collapse during/after the wet etching. [26]. The presence of these two plateaus suggests that two different etching processes may be taking place.…”

Materials and manufacturing techniques for silicon-on-insulator (SOI) wafer technology

“…First developed in order to obtain SOI wafers with very thin top silicon layers, these techniques are referred to as bond and etch-back silicon-on-insulator processes (BESOI). 30 A thin sacrifi cial layer, for example, a SiGe layer, is grown epitaxially on the initial 'donor' wafer, for example, wafer A in Fig. 1 then grown by epitaxy on the sacrifi cial layer prior to direct bonding.…”