The Effect of Surface Orientation on Silicon Oxidation Kinetics

Abstract

The rate of thermal oxidation of silicon is orientation dependent indicating that the surface orientation is an important parameter in the kinetic mechanism. However, it has not been clearly established which properties of the silicon surface control the oxidation rate. This study uses five silicon surface orientations to investigate the effect of the density of silicon atoms on planes parallel to the surface and the effect of intrinisic oxide stress on the oxidation rates. At temperatures of 700 ~ 1000 ~ and 1100~ the initial order of the rates is (110) > ( 111) > ( 311) > ( 511) > ( 100). The crossover in rate to (111) > ( 110) was observed at 700 ~ and 1000~ but not at 1100~ A qualitative correlation is obtained between the order of the initial rates and the density of atoms on the five planes. Stress effects do not appear to be dominant in the thickness regime before the rates on the (110) and (111) orientations crossover, but the ll00~ results suggest that the crossover may be related to the development of intrinsic oxide stress at lower temperatures. A revised explanation of the crossover on the (110) and ( 111) orientations based on a stress-related decrease in the transport of oxidant to the interface is proposed.

Two-Dimensional Self-Limiting Wet Oxidation of Silicon Nanowires: Experiments and Modeling

“…Therefore, the equations are given by k s0 = k s0(110) · cos 2 θ + k s0(100) · sin 2 θ (10) k s0(110) = γ k s0(100) (11) where θ is the angle between (110) orientation and the radial direction of the reaction surface. γ is the constant and its value is 1.45 in our model, which is consistent with [26].…”

Interfacial reaction-dominated full oxidation of 5 nm diameter silicon nanowires

“…The oxidation of Si takes place in two steps: the dissolution of oxygen into the oxide layer at the gas/solid interface and the diffusion of oxygen through the oxide layer. In the steady state, the oxidation rate is determined by three physical parameters: the diffusivity of the oxidant in the oxide D, the solid solubility of the oxidant in the oxide C*, and the surface reaction coefficient k. 19,30 In SiNWs having diameters greater than 5 nm, high compressive stresses are generated during oxidation, raising the diffusion energy barrier and resulting in diffusion-dominated oxidation such that the oxidation rate follows a parabolic curve, as shown in Figure 2(f). However, in the case of SiNWs 5 nm in diameter, the stress does not appear to act as a barrier.…”

“…It has been reported previously that the oxidation rate of Si depends on the orientation of its crystals. 30 Hence, the difference in orientation may have had an effect on the oxidation of SiNWs. However, this possibility can be excluded as previously reported research results indicate that the rate of oxidation along the [311] direction is lower than that noted in the case of the [110] or [111] direction.…”

Simplified process for high efficiency, self-aligned IBC c-Si solar cells combining ion implantation and epitaxial growth: Design and fabrication

“…For the BSF, the set of implantation process conditions (D ¼ 2 Á 10 15 cm À 2 and E ¼ 20 keV) leading to R □ ¼ 69 Ω/□ and i-V OC of 658 mV were chosen. Al contact line fingers were evaporated on such layer and, by using transmission line measurement (TLM) [53], its contact resistivity (ρ c ) was measured. This resulted to be equal to 0.75 70.14 mΩ cm 2 , proving the good contacting property of the layer.…”