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In this paper we examine the abruptness of increasing arsenic dopant transients obtained during in situ doping of low-temperature silicon epitaxy and compare the arsenic profiles to those obtained using phosphorus. The dopant transition lengths for arsenic are 120 to 210 nm,while those for phosphorus are at least six to eight times shorter. The arsenic transients are somewhat more abrupt at higher dopant concentrations. The deposition rate does not affect the transition length within the range of rates examined. The arsenic transients are not limited by the reactor gas-flow system. The length of the transient is similar using dichlorosilane or silane as the silicon source. A more abrupt transition can be obtained by using time-varying dopant-gas or silicon source-gas flows, but control is likely to be difficult. Both arsenic and phosphorus are incorporated more efficiently into Si 1 x Ge x than into silicon under deposition conditions typically used for each layer.

Silicon thermal oxidation was used to characterize the interaction of Si interstitials with a Si1−xGex layer and with B in Si1−xGex. Diffusion of B in a Si marker layer, positioned under a Si1−xGex layer, was monitored as excess Si interstitials were injected into the bulk by the oxidation of the Si capping layer (T=850 °C, t=18 min). The Si1−xGex layer did not affect the oxidation‐enhanced diffusion of B in the Si marker layer. Hence, Si1−xGex (x

Boron diffusion in in situ doped Si1−xGex and Si, subjected to inert‐ambient furnace annealing at 800 °C, was investigated. For Si1−xGex, the effect of biaxial compressive and tensile strain on boron diffusion was studied using Si1−xGex layers with a constant Ge content (x≊0.10 and x≊0.20) grown epitaxially on various relaxed Si1−yGey (0≤y≤0.20) substrates. Boron diffusion is primarily a function of Ge content, x in the Si1−xGex layers, and does not show a strong dependence on macroscopic biaxial strain. For Si, the effect of biaxial tension was investigated using relaxed Si1−yGey layers as substrate templates for epitaxial Si layers. As in Si1−xGex, boron diffusion in Si does not depend strongly on biaxial strain.

Aluminum gallium nitride (AlGaN) material is used in GaN-based electronic and optoelectonic devices. The Al and Ga ratio can be adjusted to produce material with different compositions and electronic properties. In this set of experiments epitaxial films of (AlxGa1−x)0.5N0.5 with x ranging from 0 to 1 were investigated. Primary composition was determined with Rutherford backscattering spectrometry (RBS). From secondary ion mass spectrometry (SIMS) profiles a correlation of secondary ion counts was made to RBS determinations of primary composition. The SIMS data was also used to determine sputter rate and the relative sensitivity factor (RSF) of O, Mg and Si in (AlxGa1−x)0.5N0.5 material. The correlation of SIMS data with RBS and knowledge of the sputter rate and RSF dependence on composition are essential for the characterization of (AlxGa1−x)0.5N0.5 films

Boron diffusion in in-situ doped Si and strained Si1−xGex (x < 0.20) epitaxial layers, subjected to inert-ambient furnace annealing, was investigated as a function of temperature (T = 750 °C - 850 °C). Boron diffusivity parameters were extracted from SUPREM IV, a process simulation program. We observed slower B diffusion in strained Si1−xGex relative to that in Si for B concentration levels ranging from 2×1017 to 3×1019 cm−3. Using relaxed graded Si1−xGex as “substrates”, we also characterized B diffusion in relaxed Si1−xGex (x < 0.60) at T = 800 °C. We propose a reaction of mobile B atoms pairing with Ge atoms to model the slower B diffusion in both fully strained and relaxed Si1−xGex.

Optimum high-frequency performance of Si/Si1-xGex heterojunction bipolar transistors can be obtained only with precise control of doping profiles within the heterostructure. With low-temperature chemical vapor deposition and advanced SIMS depth profiling techniques, we demonstrate the capability to place and measure hyperabrupt boron junctions relative to the Si/Si1-xGex heterointerface with an accuracy of 20 Angstroms. Capacitance-voltage measurements as a function of junction displacement from the heterojunction are also presented. Measurements of boron diffusivity in Si1-xGex strained layers are combined with data on boron segregation in the Si/Si1-xGex system to accurately model dopant motion across the heterointerface.