using Filestream to export to exel

Hello,
 I need help in exporting to excel from Filestream. When the data gets written to the file its only getting written in 1 line..
ex.  FAAT0010926 URCS

it should be 2 separate columns in excel.
here is part of the code.

using (streamwriter sw=new StreamWriter(filename))
{
   for (int i=0;i<1;i++)
   {
       sw.Write(firstlinedata1);
       sw.Wrtier(firstlinedata2);
       sw.Flush();
       sw.Close();
}
....

thanks in advance

    

                }