Welcome to Android Central! If your stock Internet browser app keeps crashing like that, then something is causing it to be unstable. Try booting into Safe Mode, which will disable all of your 3rd party apps temporarily. If the Internet browser stops crashing in Safe Mode, then something you installed is probably interfering with it. The tedious is part is figuring out which app, though--you may have to uninstall apps one by one until the problem goes away. https://support.t-mobile.com/docs/DOC-10248