| 1. |
- Menon, C., et al.
(författare)
-
Defect density in non-selective and selective Si/SiGe structures
- 2002
-
Ingår i: Journal of Crystal Growth. - 0022-0248 .- 1873-5002. ; 237, s. 259-263
-
Tidskriftsartikel (refereegranskat)abstract
- The epitaxial quality of Si (non-selective or selective epitaxy)/SiGe (non-selective or selective epitaxy) structures applying Si2H2Cl2 or SiH4 as the Si source has been studied. High-resolution reciprocal lattice mapping and X-ray reflectivity measurements have been used to characterise the epitaxial quality and the interfacial defects, respectively. The surface morphology of the structures was studied by atomic force microscopy. It is shown that the generation of defects in non-selective SiGe layers is strongly dependent oil the thickness of the buffer layer. Moreover, the selective growth of a Si buffer layer requires a growth temperature above 770degreesC in order to obtain a smooth layer surface, which is beneficial for the succeeding growth of the SiGe layer. The surface can also be smoothed by an annealing treatment at 900degreesC for 40 s. This annealing step is crucial to remove the interfacial defects in the case of Si/SiGe structures grown with different Si sources.
|
|
| 2. |
- Radamson, H. H., et al.
(författare)
-
Growth of high frequency SiGe heterojunction bipolar transistors structures
- 2002
-
Ingår i: Physica Scripta. - 0031-8949 .- 1402-4896. ; T101, s. 45-48
-
Tidskriftsartikel (refereegranskat)abstract
- The growth of heterojuntion bipolar transistor structures using chemical vapor deposition has been investigated. Generation of defects in selectively or nonselectively grown collector layers using arsenic as the dopant has been studied. Minimizing the defect density in SiGe base layers by optimizing the growth rate has also been investigated in detail. High resolution reciprocal lattice mapping, atomic force microscopy and secondary ion mass spectrometry have been used as the main characterization tools.
|
|
| 3. |
- Radamson, H. H., et al.
(författare)
-
Observed critical thickness in selectively and non-selectively grown Si1-xGex layers on patterned substrates
- 2002
-
Ingår i: Physica Scripta. - 0031-8949 .- 1402-4896. ; T101, s. 42-44
-
Tidskriftsartikel (refereegranskat)abstract
- Relaxation of SiGe layers grown selectively or non-selectively on oxide-patterned substrates using reduced pressure chemical vapor deposition was investigated. The influences of the buffer layer, the polycrystalline layer on the oxide and the opening size on the critical thickness for relaxation of SiGe layers have been studied in detail. High resolution reciprocal lattice mapping, atomic force microscopy and Normanski optical microscope have been used as the main characterization tools.
|
|
| 4. |
- Bentzen, Andreas, et al.
(författare)
-
Mechanisms of diffusion-enhanced thermal stability of Si/Si1-xGex/Si heterostructures grown by chemical vapor deposition
- 2004
-
Ingår i: Journal of Crystal Growth. - : Elsevier BV. - 0022-0248 .- 1873-5002. ; 261:1, s. 22-29
-
Tidskriftsartikel (refereegranskat)abstract
- The thermal stability of doped Si/Si0.8Ge0.2/Si (n-p-n or p-n-p) structures grown by reduced pressure chemical vapor deposition has been studied in correlation with the dopant in- and out-diffusion, using high-resolution X-ray reciprocal lattice mapping and secondary ion mass spectrometry as the main characterization tools. Initially, by doping the strained Si0.8Ge0.2 layer with reasonable amounts of boron, phosphorus, or arsenic, the thermal stability of the structures is shown to be dramatically increased compared to intrinsic layers. Secondly, the results show that when the dopants are present only in the Si buffer and cap layers, intrinsic Si spacer layers are required to obtain a significant enhancement in the thermal stability. These spacers reduce the interfacial dopant concentration and act as barriers for direct injection of precipitates into the SiGe layers. Finally, p-n-p and n-p-n structures were studied showing a very good thermal stability, due to enhanced out-diffusion of dopants from the SiGe layer upon in-diffusion from the adjacent layers. By employing i-Si spacers, the boron out-diffusion in a n-p-n structure was reduced, giving rise to a degradation of the thermal stability of this structure.
|
|
| 5. |
- Menon, C, et al.
(författare)
-
Loading effect in SiGe layers grown by dichlorosilane- and silane-based epitaxy
- 2001
-
Ingår i: Journal of Applied Physics. - : AIP Publishing. - 0021-8979 .- 1089-7550. ; 90:9, s. 4805-4809
-
Tidskriftsartikel (refereegranskat)abstract
- The evolution of the loading effect in Si1-xGex layers (0 less than or equal tox less than or equal to 20%) versus growth parameters has been investigated for selective and nonselective growth using silane- and dichlorosilane-based epitaxy. Various methods have been examined in order to reduce the loading effect, and their influence on the defect density will be further discussed. High-resolution x-ray diffraction and atomic force microscopy were applied as the main tools in these investigations. It is shown that SiGe epitaxy is strongly sensitive to the opening size on the patterned substrates. This dependence is affected by the chemistry of the deposition. This effect can be decreased by adding HCl to the gas mixture or decreasing the growth rate. Meanwhile, adding HCl during the growth of SiGe layers or using a low growth rate decreases the epitaxial quality of the layers. Depositing a Si seed layer prior to the growth of the SiGe layer reduces the loading effect without degrading the epitaxial quality of the layer.
|
|
