Kane sealed the Three Lions’ 2-0 Wembley win by heading home with four minutes left after Raheem Sterling had broken the deadlock in the 75th minute.
The Tottenham striker told the BBC: “It’s something we’ll never forget. It was a great performance, another clean sheet, just the perfect afternoon.
“So we’ll enjoy this one, but we know we’ve got another big one on Saturday now. We’re keeping clean sheets and we’re building confidence off that.
“This will give us more self-belief going forward, but we’ve got to make sure we get it right on Saturday now.
“We can’t switch off. We obviously want to go all the way and we’ll have a tough game coming up.”
Kane acknowledged the significance of England’s win against Germany, but stressed Southgate’s team were targeting an appearance in the final.
“It doesn’t get any bigger than this," han sa. “Knockout game against a big nation, at home when all the pressure is on, all the expectation, and we delivered.
“We should be proud of that. But the bottom line is, we don’t want to stop here. We’ve got a vision of where we want to go as a team, group of players and coaching staff, and we’re not done yet.
“We loved every second of it and hopefully we’ll be back here in the semi-final and final.”
Kane has been criticised for his subdued performances in England’s three group games and admitted it was a relief to break his scoring duck for the tournament.
“As a striker you’ve just got to be ready for the next chance, ready for the next one," han la til.
“Jack (Grealish) has put in a great cross and I was able to put it in. Amazing feeling. Any striker wants to be scoring goals, so it’s nice to score my first in this tournament.
“Hopefully I can score a couple more. Any team will be looking at us and will know that we’re dangerous.”