As of my last update in September 2021, there is no specific type of logic gate called "Schottky TTL" (STTL). However, there is a common type of logic family known as "Schottky Transistor-Transistor Logic" or simply "Schottky TTL," which I believe you might be referring to.
Schottky TTL is a variation of Transistor-Transistor Logic (TTL) that incorporates Schottky diodes in the input stage of the logic gates. Schottky diodes are semiconductor devices that have a low forward voltage drop and, when used in TTL gates, can improve the gate's switching speed and reduce power consumption compared to standard TTL gates.
The standard TTL family operates using bipolar transistors and is known for its robustness and reliability. However, it can have relatively slow switching speeds. By incorporating Schottky diodes into the input structure, STTL gates can achieve faster switching times, making them suitable for high-speed applications.
STTL logic gates are backward compatible with standard TTL gates, meaning they can be used in circuits that utilize TTL devices. They are often denoted by part numbers starting with "74S," where "S" stands for Schottky.
Please note that semiconductor technologies and naming conventions may evolve over time, so it's possible that new variations or developments related to Schottky TTL or other logic gate families have emerged since my last update.