THEORY OF TUNNELLING PROCESSES IN GERMANIUM TUNNEL DIODES. I. IMPURITY-INDUCED CURRENT; II. PHONON-ASSISTED CURRENT,
Abstract
Part I deals with a theoretical analysis of the tunnelling current in germanium caused by impurity scattering. It is shown that for a high doping level approximately 10 to the 19th power/cu cm the impurity-induced tunnelling current is important, being comparable with or even stronger than the phonon-assisted tunnelling current. Different impurities act differently; As or P induces a stronger current than Sb. It is argued that the impurity-induced tunnelling current in germanium is dominated by a second order process. An electron tunnelling from the bottom of the conduction band into the forbidden band is first scattered by the impurities into states corresponding to the (0, 0, 0) conduction band minimum, and proceeds thereon to the valence band by virtue of the junction field. A theory is proposed for such a process and a formula for the impurity-induced tunnelling current is derived. Part II deals with a theoretical analysis of the tunnelling current in Ge induced by phonon scattering. It is pointed out that this process should be primarily, a second order one: an electron tunnelling into the forbidden band from the bottom of the conduction band is first scattered by phonons into the states of the (0, 0, 0) conduction band minimum, and then makes a transition to the valence band by virtue of the junction field. It is found that the major contribution to this process is made by the lattice vibrations in a certain range (about 20A in thickness) of the junction field. The transition probability is almost directionally independent.
Document Details
- Document Type
- Technical Report
- Publication Date
- Oct 01, 1966
- Accession Number
- AD0648155
Entities
People
- Kan Tze-chao
Organizations
- Emmanuel College