Conductivity and dielectric constant of germanium at 4.2 °K were measured at a frequency of 9200 Mc/sec. The dielectric constant measured for a pure sample is 16.0±0.3. Higher dielectric constants, up to 80, were measured on n-and ^>-type samples doped with antimony or gallium. The conductivity and the change of dielectric constant are attributed to carriers in the impurity states. A positive contribution, AKb, to the dielectric constant is given by the polarization of neutral impurity atoms and a negative contribution, AK C , is associated with the conduction effect. Using AKb to estimate the ionization energy of the impurity, a value of 0.0099 ev is obtained for a sample containing 1.6X10 16 cm" 3 antimony and 0.0084 ev is obtained for a sample containing 3.7X10 16 cm" 3 gallium. Samples of higher impurity concentrations showed much higher conductivity and the effect of overlapping of impurity states is shown in the variation of impurity polarizability. The relaxation time and effective mass for the conduction in impurity states are estimated from the dc conductivity and its ratio to the microwave conductivity. Large effective masses, around 1000m, are obtained for samples of ^10 17 cm" 3 impurity concentration.

The temperature gradient zone melting process (TGZM) for doping semiconductors is being investigated for the purpose of using it to create the isolation region in a relatively small geometry thyristor. The small size of the chip puts tougher morphological requirements on this liquid zone process than in past TGZM investigations. We discuss here a number of problems encountered which include enhanced diffusion of the aluminum dopant in the silicon, lateral motion of the molten zone at the edge of the wafer, breakup and smearing of the molten zone, and outdiffusion of the aluminum into the passivating oxide layer.

A family of ultralinear npn transistors has been developed for use in the L5 coaxial‐carrier system. These 3‐GHz devices are characterized by extremely low distortion and noise figure. The transistor comprises an interdigitated base‐emitter structure with a heavily doped base grid connected to the peripheral base metal contact. The emitter contact is overlaid on the base‐emitter region. Contact metallurgy consists of a platinum silicide, titanium, platinum, and gold system. The transistor is a highly reliable device and meets all the performance requirements of the L5 system.

No abstract

No abstract