Schottky Barrier Diodes (SBD)

Structure	Symbol	Applications･Characteristics
		Used for secondary power supply rectification Low VF(low loss),large IR Fast switching speed

Unlike conventional diodes that provide diode characteristics through a PN (semiconductor-semiconductor) junction, Schottky barrier diodes utilize a metal-semiconductor junction. This results in much lower V_F characteristics (forward voltage drop) compared with PN junction diodes, enabling faster switching speeds. However, one drawback is larger leakage current (I_R), making countermeasures necessary to prevent thermal runaway.

The low forward voltage of Schottky diodes contributes to energy efficiency, making them ideal for power supplies and photovoltaic systems.

SBDs, which are often used for secondary power supply rectification, feature characteristics that can vary greatly depending on the type of metal used. Schottky diode construction involves a metal electrode bonded to an N-type semiconductor. ROHM offers a lineup of SBDs that utilize a variety of different metals.

• RB**1 series low V_F type
• RB**0 series low I_R type
• ROHM offers the RB**8 series of ultra-low-I_R diodes for automotive application

Thermal Runaway in Schottky Diodes

Schottky barrier diodes are susceptible to excessive heat generation during large current flow. As a result, the combination of high heat with increasing I_R (leakage current) can cause both the case and ambient temperature to rise. Consequently, implementing incorrect thermal design may result in the amount of heat generated to exceed the amount dissipated, which can lead to increasing heat generation and leakage current and eventually result in damage. This phenomenon is referred to as “thermal runaway.”