"A ferrous-silicate dust that is specially designed to disrupt high-energy shields and bring them down. This material is delivered by Heavy Driver cannons and will do massive damage to shields but no actual damage to the ship itself"
Shield Breakers are a dead end off Heavy Drivers, but they also can be unlocked by researching Shields Mk1. This technology is a very binary need, either you must have it or you absolutely don't need it. In most games, it's better to have and not need it than to need and not have it.

The technology can be acquired with as many as 90,000 or as little as 30,000 research points if unlocked via Heavy Drivers, but it can cost as much as 52,500 or as little as 17,500 if unlocked via Shields Mk.1. If both unlock Shield Breaker and are researched, then the cheapest path is used.

Root Technologies
And/Or Technology Research Cost % Chance to unlock Shield Breaker
Hiver Human Liir Morrigi Tarka Zuul
And Fission 0 0 0 0 0 0 0
Cruiser Construction 16,000 0 0 0 0 0 0
Or Heavy Drivers 45,000 50 60 90 95 50 80
Shields Mk.1 20,000 or 15,000 60 50 70 90 60 80
Total Chance to Unlock Shield Breaker 60.68 70.4 96.8985 99.5 71.45 83.712