Link Safe

If you are using your Galaxy in a normal way, there is no reason for the screen to turn on and stay on while charging, but it can happen if a particular developer option is enabled. If you have already set up developer access by tapping the build number in Settings multiple times, there will be an option listed called Stay awake. If this is ticked, the Galaxy screenwill stay on while charging, so it isworthgoing to Settings>General and seeing if Developer options exist. Now, if you do not have Developer options enabled and the problem is still there, you could enable them and make sure the Stay awake option is unticked. It sounds bizarre to turn on the options that can cause the problem but it is likely to work, so go to Settings>About device and tap the Build number section until Developer options are turned on.

Also,make sure you are using the charging cable that camewith your Galaxy and plug it in to a wall and not a computer. It is possible that alerts or activity on a computer can turn on an Android phone screen when it is not required. Finally, as a double check go to Settings>Display>Daydreamand make sure that this option is turned off as well. The screen will turn on when charging reaches 100%, but it should turn off very quickly after wards so hopefully one of the above solutions will work for you.