Silicon Tunnel Diode Research Articles

Model based on trap-assisted tunneling for two-level current fluctuations in submicrometer metal-silicon-dioxide-silicon diodes.

A new model is suggested to explain the characteristics of discrete two-level current fluctuations (TLF's) in metal--silicon-dioxide--silicon tunnel diodes. The model is based on trap-assisted tunneling via a single-electron trap. The trap does not act merely as a point charge in the oxide, but can function as an intermediate state for electrons that tunnel from the metal to the silicon. We show that this model can explain the large fluctuation amplitudes, and we use an atomic relaxation effect to account for the thermally activated capture and emission time constants found in our measurements. Because of the relative simplicity of the model, quantitative comparisons with experiments are possible.

Response of the silicon avalanche detector in beta, gamma, X-ray and neutron dosimetry

The responses of several of the recently described silicon avalanche detectors and tunnel diode preamplifiers to exposures of known gamma - and X-ray dose rates were measured over the energy range 34 keV to 1.33 MeV. Curves of detector isodose response and efficiency as a function of energy are presented, with a discussion of operating voltage effects. A preliminary detection efficiency is determined for exposures to 16.9 MeV neutrons and response as a function of dose is found for the beta -spectrum of 147Pm (maximum energy=230 keV). In all measurements, the tunnel diode preamplifier was used, providing very fast and low noise amplification. The measurements have demonstrated dosimetry capabilities of the avalanche detector-tunnel diode preamplifier over a wide range of energies and dose rates, and sensitivity to beta , gamma - and X-rays and to neutrons in a single detector.

An Advanced Laboratory Experiment on Tunneling in Semiconductor Diodes

This paper deals with an advanced laboratory experiment on tunneling mechanisms in tunnel diodes. The experiment measures phonon-assisted tunneling in silicon tunnel diodes. Student data are shown; the results agree nicely with previous data in the literature and with band structure calculations for Si. The student learns about band structure, phonons, tunneling techniques, and differentiation, techniques.

Tunnel Diode Switching Induced by Transient Ionizing Radiation

Radiation-induced switching in simple bistable tunnel diode circuits at radiation intensities in the range 10810-10 R/s was experimentally investigated at a 17-MeV LINAC source with 40-ns electron pulses. Silicon and gallium arsenide tunnel diodes (0.5-5 mA peak current) were operated at various levels below the peak point voltage and monitored for possible change of state following irradiation. Permissible low-voltage operating points for the bistable circuits where tunneldiodes did not switch to the high-voltage state were determined at several exposure rates. The results of the investigation have applicability in tunnel diode logic and memory array design. Tunnel diodes with higher peak-point currents (5 and 2 mA devices) were found to be more resistant to radiation-induced switching effects. Silicon devices were more consistent in response than gallium arsenide units. Silicon 4.8-mA tunnel diode circuits did not switch when initially biased at 73% peak current at a radiation exposure rate of 1.1 × 109 R/s (44 R).

High speed diffused-alloyed silicon tunnel diodes

High speed silicon tunnel diodes were made by alloying through a highly doped diffused layer. Rapid alloy cycles were achieved in a furnace using intense light sources to heat the wafers. The current density was as much as three orders of magnitude higher and peak current divided by the valley capacitance was as much as two orders of magnitude less than those of silicon tunnel diodes made from bulk doped material. The peak-to-valley current ratio was 2:1 and the voltage swing was 0·4 V compared with 3:1 and 0·6 V, respectively, for bulk phosphorus doped silicon.

Pressure effects on silicon tunnel diode

Pressure effects on silicon tunnel diode

An alloy process for making high current density silicon tunnel diode junctions

An alloy process for making high current density silicon tunnel diode junctions

Alternate Approach to the Resolution of Tunneling Current Structure by Differentiation

Structure in the current-voltage characteristics of tunneling junctions is very clearly revealed by displaying the second derivative of current with respect to voltage (d2i/dv2) as a function of junction bias. Equipment for doing this was first described by Thomas and Klein. This paper describes an alternate approach to the recovery of the first and second derivatives using a transistorized electronic circuit which, in addition to being compact and rather inexpensive, provides as good, if not better, resolution than that previously reported. The current-voltage characteristic of a typical silicon tunnel diode at 4.2°K and the first and second derivatives of this characteristic using the apparatus described are given.

Anisotropic Stress Effect on the Excess Current in Tunnel Diodes

The existence is reported of large reversible changes in the excess current of germanium, silicon, and gallium arsenide tunnel diodes subjected to highly localized stress. The relationship of this effect to the anisotropic stress effect recently reported by Rindner and Braun in conventional p-n junctions is discussed. It is suggested that both effects may arise from deep-lying electronic states associated with strain-induced lattice defects in the junction region. A consistent interpretation is presented of the tunnel diode excess current in terms of strain-induced intermediate tunneling states, and of the conventional diode current in terms of strain-induced generation-recombination centers.

Tunnel Diode Hydrostatic Pressure Transducer

A very sensitive hydrostatic pressure transducer was made using a silicon tunnel diode. The transducer consists, essentially, of a tunnel diode shunted by a resistor which satisfies the stability conditions for operation in the amplifier mode. The advantages of the tunnel diode transducers are (1) small size, (2) sensitivity, and (3) versatility. Since the p-n junction region is normally 1 mil in diameter or less, miniaturization is possible. Pressure sensitivities as high as 2 mv/v/psi were observed over a 60-psi pressure range. Expressed in terms of gauge factor, the above sensitivity is equal to about 30 000. Such high sensitivities, within narrow pressure ranges, were achieved at pressures up to 20 000 psi. The pressure range as well as the pressure sensitivity in a chosen pressure interval can be varied very simply by adjusting the values of the shunt resistor and the current through the diode-resistor combination. Even higher gauge factors can be obtained with other semiconductor materials.

Esaki Diode Pressure Transducer

Studies of the effect of point as well as hydrostatic pressures on the switching current-voltage characteristics of tunnel diodes have been reported earlier [L. Esaki and Y. Miyahara, Solid-State Electronics 1, 13 (1960); S. L. Miller, M. I. Nathan and A. C. Smith, Phys. Rev. Letters 4, 60 (1960)]. In the present work diodes were subjected to hydrostatic pressure. The transducer consists, essentially of a tunnel diode shunted by a resistor which satisfies the stability conditions for operation in the negative resistance region of the I-V characteristic. The pressure range as well as the pressure sensitivity in a chosen pressure interval can be varied by adjusting the values of the shunt resistor and the current through the diode-resistor combination. A very sensitive hydrostatic pressure transducer was made using a silicon tunnel diode. Gauge factors obtained ranged from about 2000 to 30 000, depending on the value of the shunt resistor. Pressure and temperature effects were compared for tunnel diodes made of silicon, germanium and gallium arsenide. Results show that the change in the I-V characteristics with pressure was smallest for silicon and larger for the other materials in the order listed. The order is reversed as far as the temperature effects are concerned. The advantages of the tunnel-diode transducers are (1) small size, (2) sensitivity, and (3) versatility.