Interfacial interaction between Al-1%Si and phosphorus-doped hydrogenated amorphous Si alloy at low temperature

The interfacial interaction between phosphorus-doped amorphous silicon hydrogen alloy ((n+)a-Si:H) and thermal evaporated Al-1%Si layer after furnace annealing in the temperature range from 150 to 250 °C has been investigated in detail. The scanning electron microscope photographs show that many dendrites were formed on the original (n+)a-Si:H surface at annealing temperature higher than 170 °C. Raman spectroscopy and transmission electron diffraction show that the original (n+)a-Si:H film has been converted to polycrystalline Si with the crystalline Si dendrites on top. The drastic increase (∼4 orders of magnitude) of electrical conductivity of the 200 °C annealed (n+)a-Si:H films with the Al-1%Si removed is caused by the formation of polycrystalline silicon percolation channel in the background area between dendrites. Auger spectroscopy also provides evidence that no aluminum is incorporated into the converted film during silicon recrystallization and thus no SiAl alloy is formed.