It's the same for any turbocharged vehicle (even TC petrol engines). The turbocharger, driven by the hot exhaust, will obviously heat up under load and speed.
Driven gently for the last few minutes before stopping, you won't need to worry, because there won't be enough heat generated in the turbo. But if you've climbed a hill to get to where you are stopping, your turbo would have been doing a little work and will need to be allowed to idle for a short time before turning the engine off.
Do you need a turbo timer? Not with vigilance, but it doesn't hurt. I have one in my car, but I tow a lot, and when I'm towing I flick it on for 1 minute (winter) and 2 minutes (summer).