Raducanu made light work of No.3 seed Linette in her 6-2, 6-2 win, which also marks the first time she has recorded three straight victories since her remarkable run as a qualifier in Flushing Meadows.
The 19-year-old has not dropped a set at the Korea Open and will next face top-seeded Estonian Jelena Ostapenko for a place in the final in Seoul after she beat Victoria Jimenez Kasintseva 6-2, 6-1 in their quarterfinal.
"You've got to mark the moment, in a way," Raducanu said. "I think it's pretty cool to have reached my first semifinal [since the US Open] and to build my way on the tour in the right way and to be going through the stages.
"I think it is quite a nice reward for all the hard work that I have done on the practice court and a lot of hours. It's a really nice feeling."
Raducanu was rarely troubled in the first set, which she wrapped up in 35 minutes after breaking Linette's serve twice. The Briton experienced more resistance early in the second set when she was forced to save three break points from Linette, but she broke the Pole twice more en route to a dominant victory.
It represents a welcome return to form for Raducanu, who has struggled since her US Open triumph last year. She fell sharply down the rankings to 77th and lost in the first round of her title defence in Flushing Meadows last month.