UNITY3D: Getting same result from subsequent Random.Range calls

I need to generate an array of results from a number of Random.Range calls in the Start or Awake functions. It seems the randomiser is using system time as a seed and the calls are being made within one second, so it doesn't change. How do I get more granularity, such as 1/100 of a second? I need to do this at the start of each game, so that I get a new array.