From Thin Film Materials Technology: Sputtering of Compound Materials

5.5 SELENIDES

Thin films of selenides such as ZnSe are prepared by rf sputtering from a ZnSe cathode in an Ar atmosphere. Typical sputtering conditions are shown in Table 5.52.[3] In the rf-sputtering system, the anode is perforated and substrates are placed behind the anode at floating potential to reduce the effects of the high-energy sputtered atoms and secondary electrons from the cathode.

Table 5.52: Typical Sputtering Conditions for Depositing ZnSe Thin Films

Sputtering system

RF-diode (13.56 MHz)

Target

ZnSe disk (5N)

Sputter gas

5 10 -3 torr (Ar 5N)

Spacing, target-anode

20 mm

Target-substrate

27 mm

RF-power

? 0.1 2 mA/cm 2, ? -900 -1500 V

Substrate

(100)NaCl, (111), (100)GaAs, (111)Si

Growth rate

? 0.03 1 m/hr

Transmission electron diffraction patterns from ZnSe layers sputtered onto the (100) plane of NaCl single crystals exhibit the polycrystalline or epitaxially grown monocrystalline phase shown in Fig. 5.142. The monocrystalline films consist of a single phase of cubic-ZnSe structure with the (100) plane parallel to the NaCl surface, but the polycrystalline films consist of two phases, a cubic ZnSe structure and a hexagonal ZnSe structure. The degrees of structural ordering depend on deposition rates and substrate temperatures as shown in Fig. 5.143. In this figure, a minimum epitaxial temperature T c was found to exist for a given deposition rate R, and the exponential relationship R = A exp(- Q d / kT c) was obeyed for epitaxy. Here, A

Copyright William Andrew, Inc. 2004 under license agreement with Books24x7

Products & Services
Magnetrons
Magnetrons are high-powered vacuum tubes used to generate microwave signals. Products include cavity magnetrons and sputtering magnetrons.
Cathode Emitters and Filaments
Cathodes are negatively charged electrodes used in batteries, electrolysis systems, plating, electrowinning, electron emission, and other specialized processes.
Thin Film Materials
Thin film materials are high purity materials and chemicals such as precursor gases, sputtering targets, or evaporation filaments used to form or modify thin film deposits and substrates.
Thin Film Sources
Thin film sources consist of magnetrons, evaporation thermal units, ion beams and other sources that produce deposition materials (vapors or ions) in a thin film system.
Plasma Power Supplies
Plasma power supplies are DC and RF devices used in plasma generation equipment for applications such as sputtering, plasma etching, physical vapor deposition (PVD) coating, and chemical vapor deposition (CVD) coating.

Topics of Interest

5.6 AMORPHOUS THIN FILMS Amorphous materials are prepared by the quenching of melts or vapors.[276][277] Table 5.53 summarizes these quenching processes. Among these processes, vapor quenching is...

5.2 NITRIDES Most nitrides can be characterized as high-temperature materials that show high mechanical strength. A wide variety of electronic properties, from superconductors to dielectrics, can be...

5.9 MAGNETRON SPUTTERING UNDER A STRONG MAGNETIC FIELD Under a strong magnetic field (1000 G), a high-voltage discharge (1000 V) is kept in the magnetron sputtering system. The sputtering system...

5.3 CARBIDES AND SILICIDES Carbides and silicides are known as high-temperature materials with strong mechanical strength similar to nitrides. For instance, silicon carbide (SiC) shows a high melting...

5.7 SUPERLATTICE STRUCTURES Intercalated structures consist of thin alternating layers grown by vacuum deposition such as the MBE process,[291] chemical vapor deposition including the ARE...