METAL-N-INP RECTIFYING PROPERTIES ENHANCEMENT WITH ZN BASED METALLIZATIONS AND DIFFUSION AT MODERATE ANNEALING TEMPERATURES

Rectifying contacts on n-InP using Zn based metallizations followed by moderate annealing temperature and time were studied. Diffusion of Zn atoms at the metal-semiconductor interface creates a thin p-InP layer . Pseudo-Schottky junctions were obtained with a significant barrier h eight enhancement, typically 0.2-0.25 eV. The metallization process in volved throughout the present work leads to high quality Schottky diod es within a rather simple procedure similar to this generally used to obtain good ohmic contacts. It is shown in particular that the special requirements needed for a lot of electrical measurements (e.g. C-V ch aracteristics or D.L.T.S.) can be matched without any extra complicati on. The behaviour of Schottky devices was thoroughly analysed as a fun ction of the annealing procedure. Best performances were obtained by a pplying cumulative annealing sequences, increasing the temperature whi le decreasing the time of exposure. The homogeneity of the structures was attested from a satisfactory agreement between barrier heights ded uced either from current or from capacitance measurements. A good line arity of C-2-V-T curves and low values of the series resistances were also obtained.