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A tunnel diode or Esaki diode is a type of semiconductor diode that has effectively "negative resistance" due to the quantum mechanical effect called tunneling. It was invented in August 1957 by Leo Esaki and Yuriko Kurose when working at Tokyo Tsushin Kogyo, now known as Sony .
Consequently, tunnel diode logic circuits required a means to reset the diode after each logical operation. However, a simple tunnel diode gate offered little isolation between inputs and outputs and had low fan in and fan out. More complex gates, with additional tunnel diodes and bias power supplies, overcame some of these limitations. [7]
The tunnel diode circuit (see diagram) is an example. [82] The tunnel diode TD has voltage controlled negative differential resistance. [54] The battery adds a constant voltage (bias) across the diode so it operates in its negative resistance range, and provides power to amplify the signal.
A minimum PVCR of about 3 is needed for typical circuit applications. Low current density Si/SiGe RITDs are suitable for low-power memory applications, and high current density tunnel diodes are needed for high-speed digital/mixed-signal applications. Si/SiGe RITDs have been engineered to have room temperature PVCRs up to 4.0. [23]
The current from the bias battery V b biases the diode into the center of its curve (black), where it has a negative differential resistance of r (red). The operating point and output voltage of the circuit v o is at the intersection of the tunnel diode curve and the resistor load line R (blue) .Since R < r , if the two values are close in ...
A second base diode connected antiparallel to the base diode (D 2 in Baker's schematic) will provide a low-impedance return path for removing stored base charge in the transistor. This three-diode circuit is still referred to as a Baker clamp by some sources, [14] while others only call the two-diode circuit a Baker clamp. [15]
For example, to electronically tune radio and TV receivers (varactor diodes), to generate radio-frequency oscillations (tunnel diodes, Gunn diodes, IMPATT diodes), and to produce light (light-emitting diodes). Tunnel, Gunn and IMPATT diodes exhibit negative resistance, which is useful in microwave and switching circuits. Diodes, both vacuum and ...
In electronics, the Zener effect (employed most notably in the appropriately named Zener diode) is a type of electrical breakdown, discovered by Clarence Melvin Zener. It occurs in a reverse biased p-n diode when the electric field enables tunneling of electrons from the valence to the conduction band of a semiconductor , leading to numerous ...