Self-Aligned Formation of C54 Titanium Germanosilicide Using Rapid Thermal Processing and Application to Raised, Ultrashallow Junctions

1993 ◽  
Vol 320 ◽  
Author(s):  
Stanton P. Ashburn ◽  
Douglas T. Grider ◽  
Mehmet C. ÖztÜrk ◽  
Gari Harris ◽  
Dennis M. Maher

ABSTRACTIn this paper we present results on solid state reactions between Ti and Si1−xGex alloys selectively deposited onto Si (100) substrates using rapid thermal annealing (RTA) for contact applications in novel device structures. Germanium concentrations of 0%, 30%, 50%, and 100% within the reacting Si1−xGex alloy are investigated. The Si1−xGex alloys (approximately 2500 ° thick) are deposited using rapid thermal chemical vapor deposition (RTCVD). Titanium is then deposited by evaporation. Sheet resistance measurements as a function of RTA temperature (10 second anneals) provide indications of various phases that occur during the reactions through the formation of constant sheet resistance plateaus. The RTA temperature required for the formation of a minimum resistivity phase is observed to increase for increasing Ge concentrations within the reacting Si1−xGex alloy. Using x-ray diffraction we have determined that for the reactions of Ti with Si the C49 TiSi2 metastable phase forms prior to the minimum resistivity C54 TiSi2 phase. For the reactions between Ti and Ge a minimum resistivity TiGe2 phase also with the C54 structure forms, however, this phase is preceeded not by a C49 TiGe2 structure, but by a Ti6Ge5 phase. The minimum resistivity phases for Ti reactions with 30% and 50% Ge Si1−xGex, alloy reactions also have a C54 structure with unit cell dimensions varying from that of TiSi2) to TiGe2 as the Ge concentration is increased. The grain structures for the reactions are investigated by cross-sectional transmission electron microscopy (XTEM). As the Ge concentration within the reacting alloy decreases the lateral grain size for the C54 structures increases. A self-aligned germanosilicide process is identified and used to fabricate raised, ultrashallow junctions with Ti(SiGe)2 (germanosilicide) contacts. Forward and reverse bias characterization of the junctions indicate that leakage current induced during silicidation can be eliminated using raised junctions with germanosilicide contacts.

1990 ◽  
Vol 187 ◽  
Author(s):  
E. Ma ◽  
L.A. Clevenger ◽  
C.V. Thompson ◽  
K.N. Tu

AbstractThe growth of an amorphous Ti-Si phase and subsequent formation of crystalline silicides during solid-state reactions in Ti/a-Si multilayer films have been studied using power-compensated differential scanning calorimetry, cross-sectional transmission electron microscopy, and thin-film x-ray diffraction. By analyzing calorimetric data we have determined the activation energies for the formation of the various silicides (amorphous Ti-silicide, TiSi, C49-TiSi2, Ti5Si3) as well as their heats of formation. An amorphous silicide is the first phase to form during heating and we have measured the composition profile of this amorphous layer using scanning transimission electron microscopy. Metastable phase equilibria in the Ti-Si system are discussed in light of the thermodynamic and compositional information obtained in our experiments.


1999 ◽  
Vol 562 ◽  
Author(s):  
G. Lucadamo ◽  
K. Barmak ◽  
D. T. Carpenter ◽  
C. Lavoie ◽  
C. Cabral ◽  
...  

ABSTRACTThe microstructural changes that occur during the reaction of sputter-deposited Nb/Al and Ti/Al multilayer thin-films with bilayer thicknesses ranging from 10 nm to 333 nm have been studied. The films were deposited with an overall stoichiometry of XAl3 (X = Nb,Ti) and subsequently annealed to different stages of the reaction in a differential scanning calorimeter (DSC). Data obtained from cross-sectional transmission electron microscopy (XTEM), and in situ synchrotron X-ray diffraction (XRD) experiments have provided evidence for a two-stage reaction mechanism for the formation of NbAl3. Microscopy results from a film with a bilayer period of 333 nm showed a microstructure that was consistent with two-dimensional growth in the plane of the interface. A uniform, 10 nm thick continuous layer of the product phase was formed followed by growth normal to the interface that initially consisted of larger, faceted grains. By the end of the reaction, an equiaxed NbAl3 grain structure was observed. High resolution elemental mapping using a scanning transmission electron microscope (STEM) revealed penetration of Nb into the Al layer and enhanced growth in regions where Al grain boundaries intersected the interface. Characterization of microstructure evolution in the Ti/Al system was complicated by the formation of two metastable structures consisting of cubic Ll2 followed by tetragonal DO23, and finally the equilibrium, tetragonal DO22 structure. However, the metastable phase transition temperatures were clearly isolated using the in situ XRD technique.


2003 ◽  
Vol 770 ◽  
Author(s):  
L. Maddiona ◽  
S. Coffa ◽  
S. Lorenti ◽  
C. Bongiorno

AbstractIntegration of photodetectors with high responsitivity in the near infrared (1.3-1.55 μm) on standard Si electronic circuits is important for a variety of applications in the field of on-chip, local area and long haul optical communications. In this work we report on a detailed structural and optical characterization of epitaxial Si1-xGex films and Si1-xGex /Si multilayers grown by chemical vapor deposition on (100) Si wafers. Cross-sectional transmission electron microscopy analyses show that metastable strained Si1-xGex films of few nanometer with x>40% can be deposited at low growth temperature and pressure. Absorption measurements on these films demonstrate the extension of the photo-response to 1.55 μm. Using these films as active layers Schottky integrated photodetectors have been fabricated.


1991 ◽  
Vol 238 ◽  
Author(s):  
Paul G. Snyder ◽  
Yi-Ming Xiong ◽  
John A. Woollam ◽  
Eric R. Krosche

ABSTRACTVariable angle spectroscopie ellipsometry (VASE), a nondestructive optical technique, was used to characterize two different multilayer samples, each having a low-pressure chemical vapor deposited polycrystalline silicon (poly-Si) layer. Analysis of these samples by cross-sectional transmission electron microscopy (XTEM) revealed large changes in grain size, between the undoped, as-deposited, and doped, annealed poly-Si layers. Roughness at the top of the poly-Si layers was also observed by XTEM. These features, together with the other structure parameters (thickness and composition), were analyzed ellipsometrically by fitting the measured VASE spectra with appropriate multilayer models. Each composite layer (surface overlayer, interfacial layer, and poly-Si layer) was modeled as a physical mixture, using the Bruggeman effective medium approximation. The ellipsometrically determined thicknesses were in very good agreement with the corresponding results measured by XTEM. Furthermore, VASE analysis provided additional information about the relative fractions of the constituent materials in the different composite layers. Thus, it quantitatively characterized the surface and interracial properties, and also the doping and annealing effects on the microstructure of poly-Si layers.


1999 ◽  
Vol 596 ◽  
Author(s):  
H. Fujisawa ◽  
M. Shimizu ◽  
H. Niu ◽  
K. Honda ◽  
S Ohtani

AbstractDomain structure and growth mechanism of PbTiO3 thin films were investigated using a transmission electron microscopy(TEM) from the viewpoint of size effects. At initial growth stage of (111)-oriented PbTiO3 films prepared by metalorganic chemical vapor deposition(MOCVD), triangle-shaped islands were grown on Pt(111)/SiO2/Si before becoming a continuous film. Triangular islands grew gradually in a lateral dimension. This means that PbTiO3 films grew two-dimensionally at initial growth stage. In cross-sectional TEM photomicrographs, (101)-twin boundaries (90° domain walls) and inclination of {110} or {101}-plane were observed in PbTiO3 islands. This result indicates that such small PbTiO3 islands have a tetragonal structure and could have spontaneous polarization. The minimum island which had 90° domain walls was 10nm high and 18nm wide.


2018 ◽  
Vol 787 ◽  
pp. 37-41
Author(s):  
Huan You Wang ◽  
Qiao Lai Tan ◽  
Gui Jin

InGaN/GaN multiquantum well (MQW) structures have been grown on cone-shaped patterned sapphire substrates (CPSS) by metalorganic chemical vapor deposition (MOCVD). From the transmission electron microscopy (TEM) results, we found that most of the threading dislocations (TDs) in the trench region of the CPSS were bent by lateral growth mode. Also the staircase-like TDs were observed near the slant region of the cone pattern, they converged at the slope of the cone patterned region by staircase-upward propagation, which seems to effectively prevent TDs from vertical propagation in the trench region. The associated dislocation runs up into the overgrown GaN layer and MQW, and some (a+c) dislocations were shown to decompose inside the multi-quantum well, giving rise to a misfit segment in the c-plane and a V-shape defect. From cross-sectional TEM, we found that all V defects are not always connected with TDs at their bottom, some V defects are generated from the stacking mismatch boundaries induced by stacking faults which are formed within the MQW due to the strain relaxation.


1991 ◽  
Vol 235 ◽  
Author(s):  
Yung-Jen Lin ◽  
Ming-Deng Shieh ◽  
Chiapying Lee ◽  
Tri-Rung Yew

ABSTRACTSilicon epitaxial growth on silicon wafers were investigated by using plasma enhanced chemical vapor deposition from SiH4/He/H2. The epitaxial layers were growm at temperatures of 350°C or lower. The base pressure of the chamber was greater than 2 × 10−5 Torr. Prior to epitaxial growth, the wafer was in-situ cleaned by H2 baking for 30 min. The epi/substrate interface and epitaxial layers were observed by cross-sectional transmission electron microscopy (XTEM). Finally, the influence of the ex-situ and in-situ cleaning processes on the qualities of the interface and epitaxial layers was discussed in detail.


2002 ◽  
Vol 16 (08) ◽  
pp. 1261-1267 ◽  
Author(s):  
M. P. SINGH ◽  
S. A. SHIVASHANKAR ◽  
T. SHRIPATHI

We have studied the chemical composition of alumina ( Al 2 O 3) films grown on Si(100) at different substrate temperatures by metalorganic chemical vapor deposition (MOCVD) using aluminium acetylactonate { Al(acac) 3} as the precursor. We have found that the resulting films of Al 2 O 3 contain substantial amounts of carbon. X-ray photoelectron spectroscopy (XPS) was employed to study the chemical state of carbon present in such films. The XPS spectrum reveals that the carbon present in Al 2 O 3 film is graphitic in nature. Auger electron spectroscopy (AES) was employed to study the distribution of carbon in the Al 2 O 3 films. The AES depth profile reveals that carbon is present throughout the film. The AES study on Al 2 O 3 films corroborates the XPS findings. An investigation of the Al 2 O 3/ Si (100) interface was carried out using cross-sectional transmission electron microscopy (XTEM). The TEM study reveals textured growth of alumina film on Si(100), with very fine grains of alumina embedded in an amorphous carbon-containing matrix.


1991 ◽  
Vol 236 ◽  
Author(s):  
Yung-Jen Lin ◽  
Ming-Deng Shieh ◽  
Chiapying Lee ◽  
Tri-Rung Yew

AbstractSilicon epitaxial growth on silicon wafers were investigated by using plasma enhanced chemical vapor deposition from SiH4/He/H2. The epitaxial layers were growm at temperatures of 350°C or lower. The base pressure of the chamber was greater than 2 × 10−5 Torr. Prior to epitaxial growth, the wafer was in-situ cleaned by H2 baking for 30 min. The epi/substrate interface and epitaxial layers were observed by cross-sectional transmission electron microscopy (XTEM). Finally, the influence of the ex-situ and in-situ cleaning processes on the qualities of the interface and epitaxial layers was discussed in detail.


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