Ion- and Photo-Analysis of Metal Chelate Reactions on the Semiconductor Surface

The continuing advances in miniaturization of semiconductor devices have seriously challenged contact technology. This work explored the chemical reaction involved in the bottom‐up formation of metal contacts using a linear atomic metal string chelate for CVD. The adsorption and thermal reaction of a linear dipyridylamino trichromium chelate on the GaN surface were characterized using x‐ray photoelectron spectroscopy, secondary ion mass spectrometry, and thermal programmed desorption. The chelate may react with GaN at 105 K and chemisorb on the substrate surface via bonding of the chromium atom in the central metal chain after its terminal bond was disrupted. The bonding of dipyridylamino ligands to the central metal chain remained intact during chemisorption. The chromium atom string of the chemisorbed species was inclined to the surface. A change in bonding configuration of the chelate took place as the chelate dose to the substrate was increased. The chemisorbed structure was stable on the surface in the substrate temperature range between 110 K and 260 K. Some dipyridylamino ligands may be detached from the chelate at ˜340 K. At a higher substrate temperature of ˜540 K, additional ligands may dissociate, along with the cleavage of the chemical bond in the central metal chain.