Characterization of WSix/GaAs Schottky contacts

Abstract

The Schottky diode characteristics of WSix contacts on n-type GaAs have been investigated and correlated to the film stress in WSix and crystallographic properties of the film. Experimental results show that (1) the high-temperature stability of WSix/GaAs Schottky diode characteristics depends significantly on Si content; (2) WSix/GaAs contacts exhibit very high-temperature-stable Schottky diode characteristics at Si content around 0.60, and at this Si content no metallurgical interactions between WSix and GaAs are observed by 2-MeV 4He+ Rutherford backscattering (RBS) measurements; (3) the optimum Si content for Schottky diode characteristics coincides with that for stress minimum in WSix; (4) the Schottky diode characteristics are not affected by whether WSix is crystallized or not, and a common feature of the regions where the Schottky diode characteristics are very high-temperature stable is that each consists of single-phase (W5Si3 secondary solid solution or amorphous).

Schottky barrier degradation of the W/GaAs system after high-temperature annealing

“…The thermal stability of TiN [10] and MoSi 2 [11] contacts to GaAs has also been investigated, but they were found to be unstable contacts for annealing temperatures higher than 700°C and 500°C, respectively. _The degradation of these contacts at high temperatures was believed to be connected to the interdiffusion of GaAs and the contact materials at the interface [8,11]. This explanation, however, does not seem to be applicable to the W/GaAs contact studied by Matsumoto et al The excellent electrical behavior of the W/GaAs diode after annealing at 950°C observed by Matsumoto et al might be the result of the formation of a uniform layer of -3-a W-GaAs intermetallic compound at the W/GaAs interface.…”

Chemical Vapor Deposition of Molybdenum Silicide

“…MoF6 + 2Sill4 --~ MoSi2 + 6HF + H2 [1] MoF6 + 3Sill4 --* MoSi2 + SiH3F + 5HF + 2H2 [2] MoF6 + 3Sill4 -~ MoSi2 + SiH2F2 + 4HF + 3H2 [3] MoF6 + 3Sill4 --~ MoSi2 + SiHF3 + 3HF + 4H2 [4] MoF6 + 3Sill4 --~ MoSi2 + SiF4 + 2HF + 5H2 [5] The reactions are listed in order of increasing thermochemical driving force. The Gibbs free energies for these reactions are plotted as a function of temperature in Fig.…”

Thermally stable metal/GaAs contacts

“…Since excess As is required at the interface to form anion clusters, this approach could be considered as coincident with the defect approach in which Asaa antisites are assumed to be dominant. 42 Freeouf 6. Hence, the electrical characteristics of these nitride contacts can remain relatively unchanged or even improved after annealing.…”