The semiconductor diode mainly depends on the PN junction and work. The point contact type and Schottky type, which are inseparable from the PN junction, are also included in the range of general diodes.
Crystal diodes can be divided into:
⒈ Dot contact diode
Point contact diodes are formed by pressing a metal needle on a single chip of germanium or silicon and then passing it through the current method. Therefore, the PN junction has small electrostatic capacity and is suitable for high frequency circuits.
⒉ bond type diode
Bonded diodes are formed by fusing filaments of gold or silver onto a single chip of germanium or silicon. Its characteristics are between those of point contact diode and alloy diode. Often used as a switch, sometimes also used for detection and power supply rectification (not more than 50mA).
⒊ Alloy type diode
The PN junction is formed on a single chip of N-type germanium or silicon by alloying indium, aluminum and other metals. Small forward voltage drop, suitable for large current rectification.
It has a diffusible diode
The PN junction is made by heating a single chip of N-type germanium or silicon in a P-type impurity gas at high temperature so that one part of the surface of the single chip becomes P-type. Because PN junction forward voltage drop is small, suitable for large current rectification.
⒌ mesa type diode
The PN junction is made in the same way as the diffusion junction, but only the necessary parts of the PN junction are kept and the unnecessary parts are corroded with drugs. The rest of it takes on the shape of a face, hence the name. The initial production of mesa type, is made of semiconductor materials using the diffusion method. Therefore, this type of table is called diffusion table. For this type, it seems that there are few product models for high-current rectifying and many for low-current switching.
Pictures of planar diode
In a semiconductor single chip (mainly N-type silicon single chip), the P-type impurity is diffused, and the PN junction is formed by only selectively diffusing part of the N-type silicon single chip using the shielding effect of the oxide film on the surface of the silicon chip. Therefore, there is no need to adjust the PN junction area for drug corrosion. For planar diodes, there seem to be few models for high-current rectifying and many models for low-current switching.
Alloy diffusion type diode
It is a type of alloy. Alloy materials are materials that are easily diffused. This method is suitable for manufacturing high sensitivity varactor diodes.
External-type diode
A diode formed by fabricating a PN junction using an epitaxial process. It takes great skill to make it. Because the distribution of different concentrations of impurities can be controlled freely, it is suitable for manufacturing high sensitivity varactor diodes.