Rapid Pressure Chemical Vapor Deposition Research Articles

Measurement and simulation of boron diffusion in strained Si 1− xGe x epitaxial layers with a linearly graded germanium profile

The diffusion of boron in compressively strained Si 1− x Ge x epitaxial layers with graded Ge profiles grown by rapid pressure chemical vapor deposition during furnace and rapid thermal annealing has been studied. Comparison of the Si 1− x Ge x samples to Si samples after furnace annealing (FA) and rapid thermal annealing (RTA) revealed a retarded B diffusion inside the strained Si 1− x Ge x layer. FA after RTA has only a marginal effect on B diffusion. The extracted B diffusivity from the present studies is very well comparable with available experimental and simulation results. A simple empirical expression for B diffusion is presented and incorporated into a diffusion model for dopants in heterostructures. Good agreement between the measured and simulated diffusivity is observed. It is argued that B diffusion in strained Si 1− x Ge x layers requires the inclusion of both trapping effect and strain in the formulation of the diffusion mechanism.

Studies of boron diffusivity in strained Si1−xGex epitaxial layers

Diffusion of boron in compressively strained Si1−xGex alloy layers grown by rapid pressure chemical vapor deposition has been studied as a function of Ge fractions for 0.0006⩽x⩽0.15 and annealing temperature. The comparison of the Si1−xGex samples to the Si samples after rapid thermal and furnace anneals revealed a retarded B diffusion inside the strained Si1−xGex epitaxial layers. The influence of the Ge content on the dopant diffusion was also measured and simulated, demonstrating that the diffusion of B and the extracted bang-gap change was found to decrease with the Ge alloy content, and the extracted activation energies for diffusion were found to increase with increasing Ge content in the investigated composition range. The influence of various factors on the B diffusivity is studied and their importance is discussed elaborately. A simple empirical expression for the B retardation is presented and incorporated into a diffusion model for dopants in heterostructures. Good agreement between the measured and simulated diffusivity that includes the model for strain and chemical effects is obtained.

Measurement and Simulation of Boron Diffusivity in Strained Si1 –xGex Epitaxial Layers

Diffusion of boron in compressively strained Si1 –xGex alloy layers grown by rapid pressure chemical vapor deposition has been studied as a function of the composition for 0.0006 ≤ x ≤ 0.15 and annealing temperature. The comparison of the Si1 –xGex samples to the Si samples after rapid thermal and furnace annealing revealed a retarded B diffusion inside the strained Si1 –xGex layers. The influence of the Ge content on the dopant diffusion was also measured and simulated, demonstrating that the diffusion of B was found to decrease with the Ge alloy content and annealing temperature. A simple empirical expression for the B retardation is presented and incorporated into a diffusion model for dopants in heterostructures. Good agreement between the measured and simulated diffusivity that includes the model for strain and chemical effects are obtained. By comparing with experimental values, our extracted (by using experiment and simulation) B diffusivity predicted a lower value (retardation).