Are germanium diodes temperature sensitive?

Are germanium diodes temperature sensitive?

Germanium is more temperature sensitive than silicon because it has a smaller band gap. Even at moderate temperature, a substantial number of electrons in germanium are produce from thermal generation. For example at about 120 C, the concentration of electrons and holes from thermal generation is > 1E15.

What is the effect of temperature on diodes?

An increased temperature will result in a large number of broken covalent bonds increasing the large number of majority and minority carriers. This amounts to a diode current larger than its previous diode current. The above phenomenon applies both to forward and reverse current.

What is effect of temperature on pn junction diode?

Therefore, the increase in temperature due to heating decreases both the forward resistance and reverse resistance, and in comparison, increases the instantaneous diode current, which means that heating changes the entire V−I characteristics of a p-n junction diode.

Why is germanium sensitive to temperature?

Germanium. Each has four valence electrons, but germaniumwill at a given temperature havemore free electrons and a higherconductivity. Silicon is by far themore widely used semiconductor for electronics, partly because it can be used at much higher temperatures than germanium.

Which is more sensitive to temperature germanium or silicon?

The variation of Collector cut off current with temperature is less in Silicon compared to Germanium. The structure of Germanium crystals will be destroyed at higher temperature. However, Silicon crystals are not easily damaged by excess heat.

What is the highest temperature for germanium?

The structure of germanium will be destroyed at a temperature of approximately 100°C. The maximum normal working temperature of germanium is 70°C but silicon can be operated upto 150°C.

Why is germanium more sensitive to temperature than silicon?

At room temperature, Silicon crystal has fewer free electrons than Germanium crystal. This implies that silicon will have much smaller Collector cut off current than Germanium. The structure of Germanium crystals will be destroyed at higher temperature. However, Silicon crystals are not easily damaged by excess heat.

Why leakage current is more for germanium diode?

In Germanium and Silicon diodes, leakage current is only of few microamperes and nanoamperes, respectively. Germanium is much more susceptible to temperature than silicon. For this reason, mostly Silicon is used in modern semiconductor devices.

How does temperature affect the NTC of a GE diode?

For a Ge diode this NTC is a bit higher at 2.5 mV/°C. The effect is almost perfectly linear, so if you want you can make the diode a temperature sensor by supplying it with a constant current. Reverse current increases exponentially with rising temperature.

How does temperature affect the characteristics of a Si diode?

The characteristics curve of a Si diode shifts to the left at the rate of -2.5 mV per degree centigrade change in temperature in forward bias region. In the reverse bias region, the reverse saturation current of Si and Ge diodes doubles for every 10° C rise in temperatur Loading…

What is the maximum temperature rating of a diode?

The maximum value depends on the current waveform and the cooling conditions of the device. The limiting factor on this rating is the junction temperature of the diode. The rating is usually specified at TCASE = 85 degC, for half sine wave (180 deg conduction angle).