It is my understandig that the sytax for tar is as follows:
$ [command] [switches] [file-to-create] [ file-to-include]
$ tar -czvf /temp/backup.tgz /what-ever-files-you-want-to-backup
So if we look at what you are trying to do is to create a /home/* with /backup/wet.tar.gz
you may want to confirm this with the man. That is man tar.