ULTRAVIOLET LASER-ASSISTED SURFACE-TREATMENT OF INP WITH PHOSPHINE GAS

InP surface has been treated with phosphine (PH3) gas photodecomposed by ArF excimer laser at a temperature as low as 150-degrees-C. It is shown by Auger electron spectroscopy analysis that the photolytic process of PH3 gas is capable of removing native oxide and depositing simultaneously amorphous P film on the InP surface. Moreover, hydrogenation occurs on and near the surface of InP. An enhancement of the barrier height up to 0.63 eV is demonstrated for MIS Schottky junctions with a thin P layer formed on the treated InP substrates. Furthermore, it is shown that the barrier height varies depending on work function of the Schottky metal on the treated InP. This suggests that the present process causes a reduction in the surface state density which permits weakening of the Fermi level pinning at the surface of InP.