Kinetic Modeling of Low Temperature Epitaxy Growth of SiGe Using Disilane and Digermane

Kolahdouz, Mohammadreza; Salemi, Arash; Moeen, Mahdi; Östling, Mikael; Radamson, Henry H.

doi:10.1149/2.jes113689

Cited by 8 publications

(8 citation statements)

References 27 publications

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“…An increase of the m parameter, from 2.45 (550 °C) up to 4.56 (450 °C), satisfactorily modelled the Ge content increase that occurred as temperature decreased in SiGe layers grown at 45 Torr in a showerhead reactor (17). Finally, m values increasing from 1.69 (575 °C) up to 3.23 (500 °C) were associated with SiGe layers grown at an undisclosed growth pressure in a regular RP-CVD reactor (16). The Ge2H6 massflow ranges explored (and thus the Ge content ranges probed) were rather small in Refs.…”

Section: -Experimental Detailsmentioning

confidence: 58%

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A Benchmark of Germane and Digermane for the Low Temperature Growth of Intrinsic and Heavily in-situ Boron-Doped SiGe

2016

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We have benchmarked germane and digermane for the low temperature growth of SiGe and SiGe:B (with disilane as the Si gaseous precursor). At 500°C, 20 Torr, the SiGe growth rate increased linearly with the Ge flow. It was 8 to 10 times higher with Ge2H6 than with GeH4, however. Ge atoms were otherwise 4 times more likely to incorporate in SiGe films with Ge2H6 than with GeH4. The use of GeH4 led to an exponential increase of the 20 Torr SiGe growth rate with temperature (42 kcal. mol.-1 activation energy), together with a slight linear decrease of x. The situation was different with Ge2H6. As T increased, we had a slight exponential increase of the SiGe growth rate (Ea = 15 kcal. mol.-1) and a huge linear decrease of the Ge content. Adding HCl to Si2H6 + Ge2H6 otherwise led at 500 °C, 20 Torr to a significant decrease of the growth rate, together with a significant Ge concentration increase. Finally, we have investigated the 500°C, 20 Torr growth of SiGe:B layers (with a Si2H6 + Ge2H6 + B2H6 chemistry). A marked increase of the SiGe:B growth rate with the B2H6 flow was observed, together with a less than linear decrease of the Ge concentration. The lowest resistivity, e.g. 4.3x10-4 Ω.cm, was obtained for F(B2H6)/F(H2) = 2.5x10-6. For higher B2H6 flows, we had a resistivity re-increase, which was likely due to the crystalline quality degradation then the transformation into poly-SiGe:B evidenced in X-Ray Diffraction.

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Section: -Experimental Detailsmentioning

confidence: 58%

“…mol. -1 for Si atoms (16)) and (ii) the catalysis of H desorption by Ge surface atoms, freeing sites for growth. The Ge-H bond strength, 37 kcal.…”

Section: -Experimental Detailsmentioning

confidence: 99%

A Benchmark of Germane and Digermane for the Low Temperature Growth of Intrinsic and Heavily in-situ Boron-Doped SiGe

2016

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“…All SiGe layers were grown below the critical thickness according to the published data. [15][16][17] The quality of epi-layers and SiGe/Si interface could be monitored by exposing to oxygen during epitaxy or at the interfaces. For these experiments, the oxygen partial pressure was in range of 2-1600 nTorr.…”

Section: Methodsmentioning

confidence: 99%

“…One problem with epi-layers grown at low temperatures is oxygen and moisture contamination which is rooted from epitaxy environment and the purity of the reactant gases. 14,15 An important criterion in all types of devices is the signal-tonoise ratio (SNR) which indicates the quality of the electrical signal. Noise measurement is a sensitive method which can provide accurate information about any minor defects in the crystal.…”

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confidence: 99%

Sensitivity of Signal-to-Noise Ratio to the Layer Profile and Crystal Quality of SiGe/Si Multilayers

Radamson

Moeen

Abedin

et al. 2016

ECS J. Solid State Sci. Technol.

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This study presents signal-to-noise ratio (SNR) measurements of single crystalline dots or layers of SiGe/Si in multilayer structures in terms of Ge content, interfacial and layer quality. All multilayers were processed in form of mesas and the noise behavior of electrical signal was investigated by comparing the power spectral density curves and K 1/f values. The SiGe/Si multilayer structures were also characterized by the conventional material analysis tools and the results were compared to the noise measurements. The quality of SiGe/Si interface or SiGe layer was monitored by intentional exposure to oxygen in range of 2-1600 nTorr either during or prior to SiGe growth. The results demonstrated that SNR was sensitive to the interfacial and layer quality, and the Ge content in a multilayer structure. SiGe alloys have been widely integrated in large variety of devices such as CMOS for strain engineering, 1-3 bipolar transistors, 4,5 photonic detectors, 6 bolometers, 7-9 quantum cascade lasers 10 and bio-or gas-sensors.11-13 For these applications, SiGe material is grown at low temperatures (350-650• C) where the quality of layers and interfaces plays a critical role in device characteristics. Since high strain amount is often sought then layers with high Ge content have to be grown below the critical thickness in the metastable region. One problem with epi-layers grown at low temperatures is oxygen and moisture contamination which is rooted from epitaxy environment and the purity of the reactant gases. 14,15 An important criterion in all types of devices is the signal-tonoise ratio (SNR) which indicates the quality of the electrical signal. Noise measurement is a sensitive method which can provide accurate information about any minor defects in the crystal.In this article, SiGe material is grown at low temperatures and integrated in a multilayer structure with Si barriers (e.g. SiGe/Si) where the number of periodicity, layer and interface quality were studied by noise measurements. The SiGe material was either in form of two-dimensional layer or dots. Furthermore, the integrity of epitaxial growth at low temperatures in terms of oxygen contamination was presented. A discussion of how sensitive the conventional characterization tools are compared to noise measurements for detection of defects has also been included. ExperimentalThe SiGe/Si multilayer structures were deposited on Si(100) substrates in temperature range of 350-650• C at 20 torr using reduced pressure chemical vapor deposition (RPCVD). The reactant gases for SiGe growth were GeH 4 or Ge 2 H 6 and SiH 4 or Si 2 H 6 as Ge and Si sources, respectively. All SiGe layers were grown below the critical thickness according to the published data.15-17 The quality of epi-layers and SiGe/Si interface could be monitored by exposing to oxygen during epitaxy or at the interfaces. For these experiments, the oxygen partial pressure was in range of 2-1600 nTorr. In order to determine the flux and absorption of oxygen in the reactor a residual gas analyzer (RGA) was c...

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“…[15][16][17][18] High-order silanes and germanes enable us to decrease the growth temperature owing to the low thermal energy necessary for breaking Si-Si or Ge-Ge bonds in the molecules. 17,18) The characteristics of Si 1−x Ge x film growth with high-order precursors have already been well studied by chemical vapor deposition (CVD) 15,16,[18][19][20][21] and gas source MBE. 22) In a recent study, 15) a low-temperature Si 1−x Ge x growth down to 400 °C has been achieved using high-order precursors.…”

Section: Introductionmentioning

confidence: 99%

Influence of precursor gas on SiGe epitaxial material quality in terms of structural and electrical defects

Ike¹,

Simoen²,

Shimura³

et al. 2016

Jpn. J. Appl. Phys.

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We have investigated the structural and electrical properties of n-type doped Si1− x Ge x epitaxial layers (x = 24–26%) grown by chemical vapor deposition with conventional [SiH2Cl2 (DCS)/GeH4] and high-order (Si2H6/Ge2H6) precursor combinations. X-ray diffraction, atomic force microscopy, and deep-level transient spectroscopy (DLTS) measurements were performed for characterization. The crystalline properties and surface morphology of the Si1− x Ge x layer with Si2H6/Ge2H6 grown at temperatures as low as 550 °C show good structural quality similar to that with DCS/GeH4 grown at 615 °C. On the other hand, in terms of electrical properties, the DLTS measurement reveals the existence of vacancy-related complexes in the as-grown layer with Si2H6/Ge2H6. We found that post-deposition annealing at 200 °C for the Si1− x Ge x epitaxial layer is effective for annihilating vacancy-related defects with densities down to as low as that of conventional precursors.

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Kinetic Modeling of Low Temperature Epitaxy Growth of SiGe Using Disilane and Digermane

Cited by 8 publications

References 27 publications

A Benchmark of Germane and Digermane for the Low Temperature Growth of Intrinsic and Heavily in-situ Boron-Doped SiGe

A Benchmark of Germane and Digermane for the Low Temperature Growth of Intrinsic and Heavily in-situ Boron-Doped SiGe

Sensitivity of Signal-to-Noise Ratio to the Layer Profile and Crystal Quality of SiGe/Si Multilayers

Influence of precursor gas on SiGe epitaxial material quality in terms of structural and electrical defects

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