Molybdenum deposition on clean Si(100) with a fluence as low as 1-4 mo
nolayers suffices to nucleate molybdenum disilicide. At 640 degrees C,
disilicide growth is initiated by the formation of small crystallites
of hexagonal MoSi2, separated by clean, but roughened, Si(100)-2 X 1,
as revealed by scanning tunneling microscopy, Auger electron spectros
copy, and glancing angle X-ray diffraction. At 770 degrees C, molybden
um deposition leads to tetragonal MoSi2 preferentially oriented with r
espect to the silicon substrate.