Influence of the electron beam evaporation rate of Pt and the semiconductor carrier density on the characteristics of Pt/n-GaAs Schottky contacts

Abstract

Schottky barrier diodes (SBDs) were fabricated on epitaxially grown n-GaAs materials, with different free carrier densities, by electron beam (e-beam) evaporation of Pt at various rates. The quality of the SBDs was evaluated by standard current-voltage (I-V) measurements, while the defects introduced during e-beam evaporation were characterized by deep level transient spectroscopy (DLTS). The results showed that if the GaAs was shielded during Pt deposition from stray electrons originating at the e-beam filament, high quality SBDs were formed. However, if the GaAs was not shielded during deposition, the quality of the diodes was poor and the degree to which their characteristics deviated from the ideal case increased as the total electron dose reaching the substrate increased (for slow evaporation rates) and as the free carrier density of the GaAs increased. DLTS revealed that several surface and subsurface defects were introduced during metallization without the electron shield and it is shown that these defects are responsible for the poor device quality. The nature of some of these defects depended on the free carrier density of the GaAs.

Electrical Characterization of Defects Introduced in <i>n</i>-Type N-Doped 4H-SiC during Electron Beam Exposure

“…Auret et al [1] and Coelho et al [2] have reported that metallization procedures, including electron beam deposition (EBD), induced defects at and close to the metal-semiconductor junction [3]. These defects influence the performance of the devices and alter the contacts' Schottky barrier heights [4].…”

Electrical characterization of defects introduced during metallization processes in n-type germanium

“…Some investigations regarding the defects introduced in Ge during EBD [6][7][8] and sputter deposition [9,10] have been reported. The defects introduced during these processes reside in the Ge at and close to the metal-Ge junction; they influence device performance and alter the barrier heights of the contacts [11]. The defects responsible for these barrier adjustments are formed when energetic particles reach the semiconductor surface and interact with the semiconductor.…”

Electrical characterization of defects introduced during electron beam deposition of W Schottky contacts on n-type 4H-SiC

“…It has been reported that metallization processes, such as electron-beam deposition and sputter deposition, introduce electrically active defects in measurable quantities at and close to M-S junction in conventional semiconductors such as Si, Ge and GaAs [15][16][17][18], and 6H-SiC [19]. The defects introduced influence the performance of devices and may alter the barrier height of metal-semiconductor contacts [20][21][22]. Deep-level defects responsible for barrier alterations are formed when energetic particles strike the surface of the semiconductor and interact with semiconductor creating interface states, while defects deeper in the semiconductor usually lead to levels in the band gap that trap and emit carriers.…”