The pulsed method for selecting tunnel diodes is suitable for their simultaneous rapid sorting in small batches (up to 5–8 specimens); it serves to evaluate the amplitude and speed characteristics of any diode of a batch and it contributes only a small error (for a 1-mm line thickness on the screen and an image height of 50–100 mm the error amounts to 1–2%). Translated from Izmeritel'naya Tekhnika, No. 3, pp. 37–38, March, 1967.

Tunneling currents in reverse-biased base-emitter junctions are investigated and analyzed. Guided by a simple analytic theory, shallow n+-p junctions are designed with a variety of different concentration profiles. Measurements of the dc electrical characteristics indicate a significant Zener tunneling component in the reverse diode current. The appearance of tunneling is ascertained by the temperature dependence, which also allows a clear distinction of other current mechanisms. The sensitivity of the current to the details of the doping profile is theoretically explained in terms of the maximum electric field in the junction and verified by SIMS andC-Vprofiling techniques. TheC-Vdata are analyzed in a novel way to obtain experimental data on the maximum electric field making the conclusions valid for any arbitrary junction. The implications of the presence of high electric fields in shallow junctions are discussed with respect to scaling bipolar transistors.

Implanted-diffused As layers in Si have been well-characterized and have been used in fabricating low-voltage n-p junctions. It is shown that these As layers form linearly graded junctions with a uniform B-doped background (ρ ≃ 0.006 Ω.cm). The grade constant of the As profile at the junction is known sufficiently well as a function of As dose, diffusion time, and temperature to allow quantitative use of existing tunneling and avalanche theories for the calculation of the reverse I-V curves. Following a verification of the calculated I-V curves and their temperature dependence as a function of grade constant, calculated curves are presented which correlate As implant dose and diffusion with junction breakdown voltage, breakdown impedance, and temperature coefficient of reverse voltage. The temperature coefficient is shown to change from negative to positive as the transition from tunneling to avalanche occurs. In addition, the relative importance of tunneling and multiplied-generation current as a function of current density is elucidated for any particular As layer grade constant.