THEORY OF DIFFUSION INSTABILITIES IN SEMICONDUCTORS,
Abstract
A possible mechanism for instabilities in semiconductors is considered. If carrier temperature gradients become large and directed opposite to the density gradients the net diffusion of carriers is reversed, and instabilities may arise. Suitable conditions for the instability are obtained in intrinsic or nearly intrinsic semiconductors at electric field strengths which are sufficiently high to raise the electron temperature to two or three times the lattice temperature. The temperature dependence of the collision frequency has a profound influence on the instability. Suitable materials are those with optical phonon scattering as the dominant collision process, whereas deformation potential scattering suppresses the instability. The maximum frequency for which the instability occurs is of the order of mu-p/(mu-n)(tau-n), where mu-n and mu-p are the electron and hole mobilities and tau-n is the energy relaxation time of electrons. In polar semiconductors this frequency may be well into the microwave region. (Author)
Document Details
- Document Type
- Technical Report
- Publication Date
- Jan 01, 1967
- Accession Number
- AD0652834
Entities
People
- K. Blotekjaer
Organizations
- Royal Institute of Technology