Can gated diodes replace MOSFETs?
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Can gated diodes replace MOSFETs?

Posted Date: 2024-02-05

Gate-controlled diodes are electronic devices that are area-efficient. It includes a semiconductor layer of one conductivity type, an active region of a second conductivity type formed in the semiconductor layer adjacent an upper surface of the semiconductor layer, and at least one extending substantially vertically through the active region and at least partially into the semiconductor layer trench electrode. A first end of the gated diode is electrically connected to the trench electrode, and at least a second end is electrically connected to the active region. The gated diode operates in at least one of a first mode and a second mode as a function of a voltage potential applied between the first and second terminals. The first mode is characterized by the creation of an inversion layer in the semiconductor layer substantially surrounding the trench electrode. The gated diode has a first capacitance in a first mode and a second capacitance in a second mode, the first capacitance being substantially greater than the second capacitance.

The working principle of gate-controlled diodes is based on the impact ionization effect during electron transport. When electrons enter the p-type region from the n-type region, their energy increases due to the internal electric field. When the energy of electrons reaches a certain threshold, they can collide with atoms in the p-type region and ionize them, forming new electrons and holes. This increase in electrons and holes further strengthens the impact ionization effect during electron transport.

In practical applications, the silicon carbide solution invented by Rongsi Semiconductor with integrated gate-controlled diodes with high surge current resistance integrates parallel PNP BJTs for the gate-controlled diodes, and uses the reverse-biased PN junction to reduce the effective base thickness. Reduces the recombination of minority carriers in the base area. That is, the generation of recombination current is reduced, the current density in the channel area in the surge state is alleviated, and the overall surge current resistance capability of the device is improved.

Gate-controlled diodes also have some disadvantages in some aspects. First, due to its structural characteristics, the control signal of the gate-controlled diode needs to be transmitted through an electrode, which may result in lower control efficiency, which may be limited especially in high-speed applications. In addition, due to its complex manufacturing process and high manufacturing cost, the application of gate-controlled diodes is also subject to certain limitations. In addition, gate-controlled diodes may have reliability problems under extreme conditions such as high voltage and large current, and require sufficient testing and verification.

However, with the continuous advancement of technology and in-depth research, the performance and application scope of gate-controlled diodes are also constantly improving and expanding. At present, gate-controlled diodes have been widely used in power electronics, new energy, high-speed communications and other fields, and have achieved a series of important technological breakthroughs. It is believed that in the future, with the further development of science and technology, the application prospects of gate-controlled diodes will be broader.

Gate-controlled diodes and MOSFETs are two different electronic devices with obvious differences in structure and function. Therefore, gated diodes can replace MOSFETs in some applications, but not in others.

A gate-controlled diode is an electronic device with a control signal input terminal. Its working principle is to generate an electric field inside the diode through a control signal, thereby controlling the conduction and cut-off of the diode. Because gate-controlled diodes have high-speed switching characteristics and low on-resistance, they are widely used in high-speed switching circuits and low-power circuits.

MOSFET is a widely used electronic device with the advantages of high input impedance, low drive current, and high-speed switching. Therefore, it is widely used in digital circuits, amplifiers, power control and other fields.

While gated diodes and MOSFETs are similar in some ways, they are significantly different in other ways. For example, MOSFET has lower on-resistance and higher operating voltage, which is suitable for applications requiring high voltage and large current; while gate-controlled diodes have high-speed switching characteristics and lower drive current, suitable for applications requiring high-speed response and low power applications.

Therefore, the selection of electronic devices requires evaluation and selection based on specific application requirements. In some specific applications, gated diodes can replace MOSFETs, while in other applications more suitable electronics will be used.

Review Editor: Huang Fei


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