D. Brasen

Totally relaxed GexSi1-x layers with low threading dislocation densities grown on Si substrates

We have grown compositionally graded GexSi1−x layers on Si at 900 °C with both molecular beam epitaxy and rapid thermal chemical vapor deposition techniques. Triple‐crystal x‐ray diffraction reveals that for 0.10<x<0.53, the layers are totally relaxed. GexSi1−x cap layers grown on these graded layers are threading‐dislocation‐free when examined with conventional plan‐view and cross‐sectional transmission electron microscopy. Electron beam induced current images were used to count the low threading dislocation densities, which were 4×105±5×104 cm−2 and 3×106±2×106 cm−2 Eq. 2×106 cm−2 for x=0.23 and x=0.50, respectively. Photoluminescence spectra from the cap layers are identical to photoluminescence from bulk GexSi1−x.

Rapid thermal oxidation of silicon in N2O between 800 and 1200 °C: Incorporated nitrogen and interfacial roughness

Oxynitrides can suppress the diffusion of boron from the polycrystalline silicon gate electrode to the channel region of an ultralarge scale integrated device, and are therefore important potential substrates for thin SiO2 gates. Direct oxynitridation of Si in N2O is a simple and manufacturable N incorporation scheme. We have used rapid thermal oxidation to grow O2‐ and N2O‐oxides of technological importance (∼10 nm thick) in the temperature range 800–1200u2009°C. Accurate measurements of the N content of the N2O‐oxides were made using nuclear reaction analysis. N content increases linearly with oxidation temperature, but is in general small. A 1000u2009°C N2O‐oxide contains about 7×1014 N/cm2, or the equivalent of about one monolayer of N on Si (100). Nonetheless, this small amount of N can retard boron penetration through the dielectric by two orders of magnitude as compared to O2‐oxides. The N is contained in a Si‐O‐N phase within about 1.5 nm of the Si/SiO2 interface, and can be pushed away from the interface...

A model for the FCC→HCP transformation, its applications, and experimental evidence

AbstractA model for the FCC→HCP transformation is proposed. It is envisaged that the dislocation reactionn

Elimination of dislocations in heteroepitaxial MBE and RTCVD Ge x Si 1-x grown on patterned Si substrates

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High-quality homoepitaxial silicon films deposited by rapid thermal chemical vapor deposition

n may govern the nucleation of six-layer HCP crystal. A macroscopic HCP region forms when these nuclei, located at different levels within a localized slipped region, growth into each other. The observed orientation dependence of the strain-induced martensite and the coexistence of HCP and twinned regions have been rationalized in terms of the proposed model. In addition, the supporting evidence has been developed by examining the crystallographic features of faulted regions in partially transformed Co-6.25 wt pct Fe alloy by transmission electron microscopy.

An analysis of dislocation reduction by impurity hardening in the liquid‐encapsulated Czochralski growth of 〈111〉 InP

Traditional techniques for growing Si‐Ge layers have centered around low‐temperature growth methods such as molecular‐beam epitaxy and ultrahigh vacuum chemical vapor deposition in order to achieve strain metastability and good growth control. Recognizing that metastable films are probably undesirable in state‐of‐the‐art devices on the basis of reliability considerations, and that in general, crystal perfection increases with increasing deposition temperatures, we have grown mechanically stable Si‐Ge films (i.e., films whose composition and thickness places them on or below the Matthews–Blakeslee mechanical equilibrium curve) at 900u2009°C by rapid thermal chemical vapor deposition. Although this limits the thickness and the Ge composition range, such films are exactly those required for high‐speed heterojunction bipolar transistors and Si/Si‐Ge superlattices, for example. The 900u2009°C films contain three orders of magnitude less oxygen than their limited reaction processing counterparts grown at 625u2009°C. The fi...

EFFECT OF INCORPORATED NITROGEN ON THE KINETICS OF THIN RAPID THERMAL N2O OXIDES

We have grown GexSi1-x (0 <x < 0.20,1000–3000Å thick) on small growth areas etched in the Si substrate. Layers were grown using both molecular beam epitaxy (MBE) at 550° C and rapid thermal chemical vapor deposition (RTCVD) at 900° C. Electron beam induced current images (EBIC) (as well as defect etches and transmission electron microscopy) show that 2800Å-thick, MBE Ge0.19Si0.81 on 70-μm-wide mesas have zerothreading and nearly zero misfit dislocations. The Ge0.19Si{0.81} grown on unpatterned, large areas is heavily dislocated. It is also evident from the images that heterogeneous nucleation of misfit dislocations is dominant in this composition range. 1000Å-thick, RTCVD Ge0.14Si0.86 films deposited on 70 μm-wide mesas are also nearly dislocation-free as shown by EBIC, whereas unpatterned areas are more heavily dislocated. Thus, despite the high growth temperatures, only heterogeneous nucleation of misfit dislocations occurs and patterning is still effective. Photoluminescence spectra from arrays of GeSi on Si mesas show that even when the interface dislocation density on the mesas is high, growth on small areas results in a lower dislocation density than growth on large areas.

Growth temperature dependence of the Si(001)/SiO2 interface width

InP thin films have been deposited on several types of substrates via 193‐nm excimer laser‐induced photochemical decomposition of (CH3)3In and P(CH3)3 gas‐phase precursors. The characteristics of the deposited films are studied over a wide range of conditions. A photochemical model is proposed which explains the stoichiometry and rate at which the film deposits. Approximate fluences are given for the onset of (in order of increasing fluence) In‐precursor photochemistry, P‐precursor photochemistry, CHx photochemistry, laser‐induced crystallization, and laser damage. Crystallinity of InP films deposited on (100) InP substrates has been studied by scanning electron microscopy, transmission electron microscopy, and Rutherford backscattering spectroscopy. Films range from amorphous to epitaxial, depending upon conditions (most notably fluence incident on the substrate). The best film deposited at ∼0.1 J/cm2 and at a steady‐state temperature of only ∼320u2009°C had a backscattering spectrum indistinguishable from t...