Unwanted multiple Taps

My script instantiates a prefab at point of click or touch, every time it is clicked or touched. The problem I am having, is that more than one instance of the prefab is created with every single touch. I managed to solve it for the click version.

Initially, i did this:

 if(Input.GetMouseButtonDown (0))
 {
     Ray ray = Camera.main.ScreenPointToRay(Input.mousePosition);
     Debug.DrawRay (ray.origin, ray.direction * 1000, Color.yellow);
     RaycastHit hit;
     if(Physics.Raycast(ray, out hit, 1000))
     {
         GameObject newBomb = (GameObject)Instantiate (bomb, hit.point, Quaternion.identity);
     bombOrder.Add (newBomb);
     }
 }
 if(Input.touchCount == 1 && Input.GetTouch (0).phase == TouchPhase.Began)
 {
     //place bomb at touch location
     Ray ray = Camera.main.ScreenPointToRay (Input.GetTouch(0).position);
     RaycastHit hit;
     if(Physics.Raycast (ray, out hit, 1000))
     {
         GameObject newBomb = (GameObject)Instantiate (bomb, hit.point, Quaternion.identity);
     //add bomb to list
     bombOrder.Add (newBomb);
     }
 }

When I changed GetMouseButtonDown to GetMouseButtonUp, that solved the problem. I tried the same approach on the touch-version by changing TouchPhase.Began to TouchPhase.Ended. No change, unfortunately. I'm still getting at least 2 instances per touch. Could it be a performance issue? I'm thinking if there is a slight lag-spike on instantiation, it might read multiple touches.