Phosphorus profile control in low-temperature silicon epitaxy by reduced pressure chemical vapor deposition

Suvar, Erdal; Radamson, Henry H.; Grahn, Jan

doi:10.1016/s0921-5107(01)00806-6

Cited by 8 publications

(4 citation statements)

References 11 publications

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“…Consequently, higher selectivity could be achieved through the design of dopant types, selection of appropriate dopant concentrations and sample structures, and optimization of the oxidant concentration and the oxidation time. The n-type laminated structures have serious diffusion and segregation problems, , therefore, we do not discuss the n-type selective etching in this paper.…”

Section: Results and Discussionmentioning

confidence: 99%

Selective Digital Etching of Silicon–Germanium Using Nitric and Hydrofluoric Acids

Zhu

Zhang

et al. 2020

ACS Appl. Mater. Interfaces

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The digital etching characteristics of p+ Si and Si0.7Ge0.3 using the combinations of HNO3 oxidation and BOE oxide removal processes were studied. Experiments showed that oxidation saturates with time due to low activation energy. A physical model was presented to describe the wet oxidation process with nitric acid. The model was calibrated with experimental data and the oxidation saturation time, final oxide thickness, and selectivity between Si0.7Ge0.3 and p+ Si were obtained. The digital etch of laminated Si0.7Ge0.3/p+ Si was also investigated. The depth of the tunnels formed by etching SiGe layers between two Si layers was found in proportion to digital 2 etching cycles. And oxidation would also saturate and the saturated relative etched amount per cycle (REPC) was 0.5 nm (4 monolayers). A corrected selectivity calculation formula was presented. The oxidation model was also calibrated with Si0.7Ge0.3/p+ Si stacks, and selectivity from model was the same with the corrected formula. The model can also be used to analyze process variations and repeatability. And it could act as a guidance for experiment design.Selectivity and repeatability should make a trade-off.

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Section: Results and Discussionmentioning

confidence: 99%

Selective Digital Etching of Silicon–Germanium Using Nitric and Hydrofluoric Acids

Zhu

Zhang

et al. 2020

ACS Appl. Mater. Interfaces

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“…This is quite in agreement with the works of Jang et al [34], who have noted that the growth rate reduction, severe for Si:P [34][35][36], gets less and less pronounced as the Ge concentration increases. We are also faced, as in Si [35,38], with some significant P surface segregation, as evidenced by the large decay lengths (especially at the intrinsic SiGe on SiGe:P interfaces) in SIMS (see figure 9).…”

Section: N-type Doping Of Sigementioning

confidence: 93%

“…We have therefore studied the phosphorous doping of SiGe as a function of the Ge concentration in-between 20% and 30%. Although data are easily found on the phosphorous doping of Si using PH 3 as a gaseous precursor (see for example [34][35][36][37][38]), papers on the phosphorous doping of SiGe are rather scarce indeed [34,35,39]. The only extensive published work is the one by Jang et al [34] in very low pressure CVD (P ∼ 7 mTorr) at 620 We have therefore grown the following kind of sample: a SiGe graded layer, with a constant composition, nearly fully relaxed 1.8 µm thick SiGe layer sitting on top.…”

Section: N-type Doping Of Sigementioning

confidence: 99%

Reduced pressure chemical vapour deposition of SiGe virtual substrates for high mobility devices

Hartmann

Bogumilowicz

Holliger

et al. 2003

Semicond. Sci. Technol.

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We have studied the strain state, film and surface morphology of SiGe virtual substrates grown by reduced pressure chemical vapour deposition (RP-CVD). The macroscopic strain relaxation and the Ge composition of those virtual substrates have been estimated in high resolution x-ray diffraction, using Omega-2Theta scans around the (004) and (224) orders. Typically, linearly graded Si 0.7 Ge 0.3 virtual substrates 5 µm thick are 96% relaxed. From transmission electron microscopy, we confirm that the misfit dislocations generated to relax the lattice mismatch between Si and SiGe are mostly confined inside the graded layer. The threading dislocations density obtained for Ge concentrations of 20% and 27% is indeed typically of the order of (7.5 ± 2.5) ×10 5 cm −2 . The surface roughness of the relaxed SiGe virtual substrates increases significantly as the Ge concentration approaches 30%. We find for the technologically important Ge concentration of 30% a surface root mean square roughness of 5 nm, with an undulation wavelength for the cross-hatch of the order of 1 µm. We have also studied the electronic quality of our RP-CVD grown SiGe virtual substrates. We have grown a MODFET-like heterostructure for this purpose, with a buried tensile-strained Si channel 8 nm thick embedded inside SiGe 31%. We have obtained a well-behaved two-dimensional electron gas in the Si channel, with electron sheet densities and mobilities at 1.45 K of 5.7 × 10 11 cm −2 and 180 000 cm 2 V −1 s −1 , respectively.

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“…The higher Ge content demonstrates that Cl removed preferably the Si atoms at the surface reactions. This result also can be explained by the different relationship of gas flow ratio and Ge concentration with SiH 4 and SiH 2 Cl 2 gaseous precursors [ 32 , 43 ]. Another explanation was that Ge atoms increased hydrogen desorption, then increasing free nucleation sites [ 44 ].…”

Section: Resultsmentioning

confidence: 99%

Growth and Selective Etch of Phosphorus-Doped Silicon/Silicon–Germanium Multilayers Structures for Vertical Transistors Application

Lin

et al. 2020

Nanoscale Res Lett

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Vertical gate-all-around field-effect transistors (vGAAFETs) are considered as the potential candidates to replace FinFETs for advanced integrated circuit manufacturing technology at/beyond 3-nm technology node. A multilayer (ML) of Si/SiGe/Si is commonly grown and processed to form vertical transistors. In this work, the P-incorporation in Si/SiGe/Si and vertical etching of these MLs followed by selective etching SiGe in lateral direction to form structures for vGAAFET have been studied. Several strategies were proposed for the epitaxy such as hydrogen purging to deplete the access of P atoms on Si surface, and/or inserting a Si or Si0.93Ge0.07 spacers on both sides of P-doped Si layers, and substituting SiH4 by SiH2Cl2 (DCS). Experimental results showed that the segregation and auto-doping could also be relieved by adding 7% Ge to P-doped Si. The structure had good lattice quality and almost had no strain relaxation. The selective etching between P-doped Si (or P-doped Si0.93Ge0.07) and SiGe was also discussed by using wet and dry etching. The performance and selectivity of different etching methods were also compared. This paper provides knowledge of how to deal with the challenges or difficulties of epitaxy and etching of n-type layers in vertical GAAFETs structure.

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Phosphorus profile control in low-temperature silicon epitaxy by reduced pressure chemical vapor deposition

Cited by 8 publications

References 11 publications

Selective Digital Etching of Silicon–Germanium Using Nitric and Hydrofluoric Acids

Selective Digital Etching of Silicon–Germanium Using Nitric and Hydrofluoric Acids

Reduced pressure chemical vapour deposition of SiGe virtual substrates for high mobility devices

Growth and Selective Etch of Phosphorus-Doped Silicon/Silicon–Germanium Multilayers Structures for Vertical Transistors Application

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