부산대학교 도서관

Current limiters based on the high-field saturation of electron-drift velocity in germanium have been fabricated by making two closely spaced ohmic contacts to a surface n-layer diffused into Ge. In operation, current flows from contact to contact through the n-layer. Current saturation begins at a voltageV_{s} = E_{s} d, where d is the contact spacing and E s is the field for saturation of electron drift velocity. Generally, in order to work at reasonable signal levels (volts and milliamperes) a structure small in all dimensions is required. A diffused-layer structure provides a convenient way of meeting this requirement and, at the same time, has, first, a high surface-to-volume ratio which facilitates heat removal and, second, a p-n junction which minimizes conductivity modulation by removing avalanche-generated holes. Limiters withd \cong 2µ, and 10 µ × 10 µ contacts, were fabricated on Sb-diffused layers of 10 3 -Ω sheet resistance and ∼10 17 cm -3 surface concentration. Limiting current was ∼2.5 mA and limiting extended from ∼2 to 16 V. The conductance in the limiting range was ∼40 µmho and a contact-to-contact capacitance was ∼0.1 pF.