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Avalanche breakdown (or the avalanche effect) is a phenomenon that can occur in both insulating and semiconducting materials. It is a form of electric current multiplication that can allow very large currents within materials which are otherwise good insulators. It is a type of electron avalanche.
NXP 7030AL - N-channel TrenchMOS logic level FET IRF640 Power Mosfet die. The power MOSFET is the most widely used power semiconductor device in the world. [3] As of 2010, the power MOSFET accounts for 53% of the power transistor market, ahead of the insulated-gate bipolar transistor (27%), RF power amplifier (11%) and bipolar junction transistor (9%). [24]
The first paper dealing with avalanche transistors was Ebers & Miller (1955).The paper describes how to use alloy-junction transistors in the avalanche breakdown region in order to overcome speed and breakdown voltage limitations which affected the first models of such kind of transistor when used in earlier computer digital circuits.
For a device that makes use of the secondary breakdown effect see Avalanche transistor. Secondary breakdown is a failure mode in bipolar power transistors. In a power transistor with a large junction area, under certain conditions of current and voltage, the current concentrates in a small spot of the base-emitter junction.
The device operates by shunting excess current when the induced voltage exceeds the avalanche breakdown potential. It is a clamping device, suppressing all overvoltages above its breakdown voltage. It automatically resets when the overvoltage goes away, but absorbs much more of the transient energy internally than a similarly rated crowbar device.
With the vertical structure, the component area is roughly proportional to the current it can sustain, and the component thickness (actually the N-epitaxial layer thickness) is proportional to the breakdown voltage. [75] Power MOSFETs with lateral structure are mainly used in high-end audio amplifiers and high-power PA systems.
Enhancement-mode MOSFETs (metal–oxide–semiconductor FETs) are the common switching elements in most integrated circuits. These devices are off at zero gate–source voltage. NMOS can be turned on by pulling the gate voltage higher than the source voltage, PMOS can be turned on by pulling the gate voltage lower than the source voltage.
Charge injection, where hot carriers generated by avalanche breakdown are injected into the oxide layer. Catastrophic ESD failure modes include: Junction burnout, where a conductive path forms through the junction and shorts it; Metallisation burnout, where melting or vaporizing of a part of the metal interconnect interrupts it