Accession Number:

AD0652834

Title:

THEORY OF DIFFUSION INSTABILITIES IN SEMICONDUCTORS,

Descriptive Note:

Corporate Author:

ROYAL INST OF TECH STOCKHOLM (SWEDEN) MICROWAVE DEPT

Personal Author(s):

Report Date:

1967-01-01

Pagination or Media Count:

66.0

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-pmu-ntau-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

Subject Categories:

  • Solid State Physics

Distribution Statement:

APPROVED FOR PUBLIC RELEASE