Which diode is more stable under high temperature conditions?

一, High temperature failure mechanism of traditional silicon-based diodes
1. Temperature sensitivity of PN junction diodes
Standard silicon PN junction diodes exhibit a dual risk of failure at high temperatures:

Positive characteristic degradation: For every 1 ℃ increase in temperature, the forward voltage drop decreases by about 2mV, resulting in an increase in conduction loss. For example, at 150 ℃, the forward voltage drop of the 1N4007 rectifier diode decreases from 0.7V at room temperature to 0.4V, but the conduction current increases threefold due to thermal excitation effect, causing local overheating.
Extended reverse recovery time: The lifetime of minority carriers is prolonged at high temperatures, and the reverse recovery time (trr) is extended from 500ns at room temperature to over 2 μ s, resulting in significant switching losses in high-frequency switching applications. A case study of an industrial frequency converter shows that when the ambient temperature rises from 25 ℃ to 125 ℃, the switching loss of traditional fast recovery diodes increases by 47%, resulting in IGBT module junction temperature exceeding the standard.
2. Leakage current crisis of Schottky diodes
Although silicon-based Schottky diodes have low forward voltage drop (0.2-0.4V) and fast switching characteristics, their metal semiconductor junction exposes fatal defects at high temperatures:

Reverse leakage current index growth: For every 10 ℃ increase in temperature, the leakage current doubles. At 175 ℃, the leakage current of MBR2045CT Schottky diode can reach 10mA, far exceeding its rated reverse current (5 μ A @ 25 ℃). The test data of a car charger shows that when the ambient temperature reaches 125 ℃, the leakage current of traditional silicon Schottky diodes leads to a 3.2% decrease in system efficiency.
Risk of thermal runaway: Joule heating generated by leakage current forms a positive feedback loop with ambient temperature. An experiment showed that in an environment of 200 ℃, an uncooled silicon Schottky diode burns out due to thermal runaway within 30 seconds.
3. Voltage imbalance of Zener diode
Zener diodes face dual challenges at high temperatures:

Zener voltage drift: With a temperature coefficient of -2mV/℃, the output voltage of the 24V voltage regulator may deviate to 22.8V at 150 ℃, affecting the stability of precision circuits.
Maximum dissipated power attenuation: The thermal resistance increases with temperature, and the actual dissipated power of a certain 1W voltage regulator tube drops to 0.3W at 125 ℃, resulting in overheating and damage to the device.
二, High temperature breakthrough of wide bandgap material diode
1. SiC Schottky diode: redefining high-temperature conductivity
Silicon carbide materials achieve high-temperature stable operation based on three major characteristics:

Wide bandgap suppresses leakage current: With a bandgap width of 3.2eV, the intrinsic carrier concentration of SiC at 200 ℃ is only 1/10 of that of silicon. Experimental data shows that the leakage current density of C3D02060A SiC Schottky diode at 200 ℃ is only 0.1 μ A/cm ², which is three orders of magnitude lower than that of silicon devices.
High breakdown field strength reduces conduction resistance: A breakdown field strength 10 times that of silicon (3MV/cm) allows for the use of thinner drift layers. The conduction resistance of a 1200V SiC Schottky diode is only 0.8m Ω, which is 90% lower than that of a silicon PIN diode and reduces conduction loss by 75%.
Optimizing heat dissipation with high thermal conductivity: A thermal conductivity of 4.9W/(cm · K) enables rapid heat transfer to the heat dissipation substrate. Tests on an electric vehicle motor controller have shown that using SiC Schottky diodes reduces device junction temperature by 40 ℃ and improves system efficiency by 2.3% compared to silicon solutions.
2. Structural innovation: Eliminating minority carrier storage
SiC Schottky diodes adopt a metal semiconductor barrier structure, completely eliminating the minority carrier injection recombination process in PN junctions, and their reverse recovery charge (Qrr) is only 1/20 of that of silicon fast recovery diodes. At a switching frequency of 100kHz, the switching loss of a 650V SiC Schottky diode is reduced by 82% compared to silicon devices, allowing the power system to operate at high frequencies above 200kHz and reducing the volume of magnetic components by 60%.

三, Performance verification of typical application scenarios
1. In the field of new energy vehicles
The Tesla Model 3 motor controller uses Cree C3M0075120K SiC MOSFET and matching Schottky diode to achieve:

Switching frequency increased to 50kHz, inductor volume reduced by 40%
The system efficiency reaches 98.5%, which is 1.2% higher than the silicon solution
Range increased by 5-8%
2. Control of industrial high-temperature furnaces
The power system of a continuous casting machine in a certain steel enterprise adopts ROHM SCH2080KE SiC Schottky diode. After continuous operation for 20000 hours at 150 ℃ environment:

The leakage current remains stable below 0.5 μ A
The device failure rate is 0
The system maintenance cycle has been extended from 3 months to 2 years
3. Aerospace power supply
The power system of the European Space Agency's Sentinel-6 satellite uses Infineon IDH06G65C5XKSA1 SiC Schottky diodes. During the vacuum cold and hot cycling test from -180 ℃ to+150 ℃:

Parameter drift<0.5%
Radiation resistance up to 100krad (Si)
Weight reduced by 30% compared to silicon solution