INVESTIGATIONS ON AU, AG, AND AL SCHOTTKY DIODES ON LIQUID ENCAPSULATED CZOCHRALSKI-GROWN N-GAAS[100]

The Schottky barrier heights of metals Au, Ag, and Al fabricated by va cuum vapor deposition on liquid encapsulated Czochralski (LEC) grown u ndoped n-type GaAs (n = 2.35 x 10(15) cm(-3)) were measured with curre nt-voltage (I-V) and capacitance-voltage (C-V) techniques. Good ohmic contacts were obtained through an after deposition anneal at 430 degre es C for two minutes in an argon gas atmosphere. In the as-deposited s tate, Au, Ag, and Al gave very similar I-V characteristics for n-type substrates with the barrier height q phi(b) = 0.81-1.16 eV and idealit y factor n = 1.02-1.15. The C-V measurement also gives the same value of barrier height. The distribution of carrier concentration along the radial distance of the wafer is of 'M' shape. The Al/GaAs interfaces give the nonideal rectification behavior. The Au/GaAs interfaces give the near ideal rectification behavior. The barrier height of this inte rface is 0.89-0.92 eV and the ideality factor is about 1.10-1.19. Elec tron traps in the wafer have been found by constant capacitance deep l evel transient spectroscopy (CC-DLTS). Mainly the EL2, EL6, and EL3 (E I1) trap levels are prominent.