Point Contact Diode vs Hot Carrier Diode-Difference between point contact diode and hot carrier diode
This page compares Point Contact Diode vs Hot Carrier Diode and mentions difference between Point Contact Diode and Hot Carrier Diode(Schottky diode).The advantages and disadvantages of Point Contact Diode and Hot Carrier Diode(Schottky diode) are also mentioned.
The different types of diodes are designed and developed based on applications of use viz. GUNN diode, PIN diode, Varactor diode, Tunnel diode, normal P-N Junction diode, Zener diode, Schottky diode, Impatt diode, Trapatt diode, baritt diode, Point Contact Diode and Hot Carrier Diode etc. Refer diode tutorial as well as links provided below to know more.
Point Contact Diode
• Construction: It is basically a piece of semiconductor material and fine wire making contact with semiconductor part.
Earlier germanium was used as semiconductor material in point contact diode design.
Now-a-days P-type semiconductor is used as anode and fine tungsten wire as cathode.
• It has very small capacitance as wire makes contact to small area of the semiconductor. Hence it is known by the name Point Contact Diode.
• Function: The current flows from cathode to anode very easily. Here fine wire acts as cathode and semiconductor acts as anode. The current does not flow very easily from anode to the cathode terminals.
Advantages and disadvantages of point contact diode
• Ideal for low signal applications
• extremely low capacitance
• widely used in microwave mixers and detectors.
• They are very delicate and hence shock and vibration should be avoided during handling
• they can not withstand very high power
Hot Carrier Diode or Schottky diode
• Construction: It is simple N-type silicon along with thin metal layer deposition.
The semiconductor acts as cathode while metal acts as anode.
Nickel chromium, aluminium and gold are used as metal in Hot Carrier Diode.
It is also known as Schottky diode.
• It has tiny junction capacitance due to small size.
• It has lower bias voltage.
Advantages of Hot Carrier Diode or Schottky diode
• Ideal for mixing and signal detection applications. Hence widely used in mixers and modulator circuits.
• They are used in switches at microwave frequencies due to very high frequency response.
Difference between point contact diode and hot carrier diode
Following are the major difference between point contact diode and hot carrier diode or schottky diode:
➨In RF Mixer, point contact diodes are better at low LO levels while schottky diodes are better at high LO levels.
➨In detector, point contact diode provides better performance while hot contact diode is worst by about 30 dB compare to point contact.
➨Point contact diode has high voltage output at low levels while Hot carrier diode has low voltage output at low levels. Due to this fact, Point Contact diode has lower saturation level while Hot Carrier Diode has higher saturation level.