Photon assisted growth of HgTe by metalorganic chemical vapor deposition

Photon assisted metalorganic chemical vapor deposition (MOCVD) of HgTe by the reaction of mercury and diethyltelluride (DETe) on CdTe substrates is reported. The growths were done at 380-450°C and subatmospheric pressure, with helium as the carrier gas. A simple kinetic model for the MOCVD growth is presented. The model yields the growth rate as a function of the gas-phase partial pressures of the constituents in various limiting cases, and is corroborated by experimental results. The apparent activation energy for growth without photons (33-49 kcal/mol) exceeds the activation energy of pyrolysis of DETe (∼25 kcal/mol) and is significantly reduced in photon assisted growth (18-28 kcal/mol). The effect of photon assisted growth on morphology, thickness uniformity, and location along the susceptor is also presented and discussed.