I recommend poles after the jump. It'll steal his focus away from his actions in order for him to get over them. If you'd like to go bigger, grid work would help as well, whether all one size, or increasing the size as you go.
Put the jump closer to the fence, loosen your rein and let him run into it a few times. If that doesn't work try having someone stand 6 strides out with a bucket of grain. If your horse is food driven that'll make them stop. Take the grain away after you've tried it a few times. Repeat until it sets in.