High germanium content SiGe virtual substrates grown at high temperatures

High-temperature growth of very high germanium content SiGe virtual substrates

“…Those data points have been put to good use for the elaboration of high-quality SiGe virtual substrates with final Ge concentrations in-between 20% and 50%. Their structural properties have been discussed as a function of the growth temperature, the grading rate, the SiGe growth rate and the final Ge concentration [16,17]. In this paper, we will extend those findings by focusing on the growth kinetics of SiGe in the 0% to 100% Ge concentration range.…”

“…3), some severe quartz wall coating would occur for high Ge content virtual substrates grown in one step, altering the growth kinetics and inducing some significant particular contamination (flaking) [19]; (ii) it minimizes the strong surface roughening that occurs when ramping up the Ge concentration to high values [11,12,16]; (iii) it minimizes the threading dislocations bunching that results from rough surfaces and allows the threading arms of newly nucleated misfit dislocations to move, thereby minimizing the overall threading dislocation density [11].…”

“…9. For a growth temperature equal to 850 1C, we have previously shown that the field and the pile-up TDDs were more or less constant at 4 Â 10 5 and 1-2 Â 10 5 cm À2 for SiGe virtual substrates grown at 850 1C with Ge contents in-between 20% and 50% [16]. Growing higher Ge concentration SiGe layers (also at 850 1C) on top of polished Si 0.49 Ge 0.51 virtual substrates leads to a monotonic decrease of the field threading dislocations density (from 4 Â 10 5 cm À2 for ½Ge ¼ 50% down to slightly more than 1 Â 10 5 cm À2 for ½Ge ¼ 88%).…”

Reduced pressure chemical vapor deposition of Ge thick layers on Si(001), Si(011) and Si(111)

“…For such thick Ge layers, the surface presents a regular morphology which is sort of a convolution inbetween mounds and a cross-hatch pattern, i.e. undulations along the /11 0S directions, as in SiGe virtual substrates [27]. The presence on the hillsides of large terraces bordered by bi-atomic steps should also be highlighted.…”

Growth and structural properties of SiGe virtual substrates on Si(100), (110) and (111)

“…Finally, (11 0) tensily strained Si pMOSFETs (pseudomorphic epitaxy of Si on top of SiGe-On-Insulator substrates fabricated thanks to the Ge condensation technique) are characterized by hole mobilities superior to the one in tensily strained Si(1 0 0) [5]. The SmartCut TM industrial process can be used to fabricate (1 0 0) strained silicon-on-insulator (sSOI) substrates [2,6,7]. The very high tensile strain in the top Si layer (more than 3 GPa for Si 0.5 Ge 0.5 virtual substrates (VS) [8]) combined with a low threading dislocation density (around 10 5 cm À2 [8]) yields vastly enhanced (1 0 0) fully depleted-SOI device performances [9,10], with an increase of both electrons and holes mobilities [11,12].…”