The cloaking device in the TIE Phantom, utilized stygium crystals and could be used to track other ships unseen until the moment of firing, thus getting the jump on their enemy. The Phantom was armed with three laser cannons mounted on its three wings, and two body-mounted laser cannons. It required two pilots for operation.
The TIE Phantom had slightly above normal firepower for a starfighter of its class. This stealth fighter could move through space neither spotted on sensors nor by any pilot until they were ready to strike. However, on a TIE Phantom's sensors, cloaked TIE Phantoms would show up as sensor anomalies.
The greatest advantage of that craft was that they had a built in mechanism that allowed the pilot to fire its lasers at any time, and have the device automatically shut off and turn back on after every volley. This in effect allowed the TIE Phantom to be virtually invisible 99 percent of the time.
The ships were typically sent in small, guerilla strike squads instead of large squadrons because groups of them would not be able to see each other. This hindered their production and overall usefulness in large-scale battles.
The TIE Phantom was the brainchild of Grand Admiral Martio Batch, after the development of the hibridium-based cloaking device. Wanting to recreate the successful stygium cloaking screen used in the Sith Infiltrator, he ordered the superlaser platform Tarkin to the planet Aeten II, whose mines, the only known source of the rare stygium crystal, had dried up long before. Batch used the Tarkin to shatter the planet, releasing thousands of the crystals to be used in Batch's new project.
The TIE Phantom was a heavily modified version of a stock V38 assault fighter—leading some to refer to the Phantom TIEs by this designation—and initial prototypes were tested near Dreighton. When preliminary tests were completed, Darth Vader took control of the project and ordered the full scale production of the Phantom. The first wave of those was Sigma Squadron.
The TIE Phantom was first deployed after the Rebel Alliance deployed the B-wing starfighter, and destroyed three X-wings in a demonstration. The YT-1300 light freighter Corellia Star was able to find out about the TIE Phantom project, but was captured on Dreighton trying to return to the Rebel Alliance Fleet.
- Credit to Wookieepedia for the above information