Dm_?

Definition

Prefactor of diffusivity.

Interrogation mark (?) is used to indicate the particle for which the parameter is defined, for instance, Dm_Ci is the prefactor of migration for interstitial carbon.

Involved particles

Any particle.

Units

Square centimeters per second (cm2/s).

Related physical magnitudes

• Diffusivities: Dm_? is the prefactor of diffusivity of any particle.

Related DADOS mechanisms

• Particles jumps: Dm_? is proportional to the prefactor of Jump frequency of the particle.

Comments

1. For some immobile species, such as B, As, C,... the diffusivity prefactor is usually set to zero. This is due to the fact that they only diffuse by means of I and V, and do not diffuse only by themselves. See effective diffusivity.

2. For these particles, neutral interstitials and vacancies, it is usual the use of the product of diffusivity and concentration in equilibrium to indicate the flux:  C0relEq_? · Dm_?. When one of this parameters is modified, the other should me properly changed in order to maintain the results, at least at annealing temperatures.

    

Em_?

Definition

Migration energy.

Interrogation mark (?) is used to indicate the particle for which the parameter is defined, for instance, Eb_Ci is the migration energy for interstitial carbon.

Involved particles

Any particle.

Units

Electron-volts (eV).

Related physical magnitudes

• Diffusivities: Em_? is the activation energy of diffusivity of any particle. If the particle is an impurity-"native defect" pair, it affects to the effective diffusivity of the dopant. However, if the particle is a native defect (either neutral or charged), it affects the self-diffusivity.

Related DADOS mechanisms

• Particles jumps: Em_? affects the Jump frequency of the particle.