I am being stalked and harassed and my work cant or wont help me any advice

I have been stalked by a creepy guy at my work for around 2 years now may not be accurate I am bad with time but at first I didn't notice anything really but one day he was just in my work area stairing dead at me for about 2 minutes then I asked if he needed something then he left the next time I noticed he staired at me for my entire lunch brake and now I catch him peaking around corners at me every day and one day I was in his area with another coworker looking for a part and he came up behind me and put his hand on my back and ran it down to my butt and told my boss I told hr and nothing has been done and it is every day he even waits after work and lingers around to just stair at me with a big grin on his face and I feel hopeless and dont know what to do the only other choice I can find is leaving my job but that is easier said than done dose anyone have any advice