The Ga2O3(Gd2O3) dielectric film was previously discovered to passivate the GaAs surface effectively. We have investigated the systematic dependence of the dielectric properties of (Ga2O3)1−x(Gd2O3)x on the Gd (x) content. Our results show that pure Ga2O3 does not passivate GaAs. Films with x⩾14% are electrically insulating with low leakage current and high electrical breakdown strength. Furthermore, a low interfacial density of states was attained in films with x⩾14%. The results show the important role of Gd2O3 in the (Ga2O3)1−x(Gd2O3)x dielectric films for effective passivation of GaAs.

Sputter-deposited non-stoichiometric tantalum nitride films are used for laser-trimmed thin-film resistors owing to their stability and processability. The films are stabilized by heating in air to form a passive Ta,O, film. This passive film can he destroyed if the resistors are exposed to aggressive thermal or chemical conditions. Thus we have studied sputtered TaN films and resistors deposited on SiO, and AI,O, substrates and exposed to either KOH solutions or air at 250-500°C for various times. The oxidized films have lbeen characterized with Auger electron spectroscopy (AES), x-ray photelectron spectroscopy (XPS), x-ray absorption near-edge spectroscopy (XANES) and extended x-ray absorption fine structure (EXAFS). Chemical shifts in the N O 0 Auger spectrum have been used to show that the initial fraction of deposited TaN reacts with the SiO, surface to form Ta,O,. X-ray photoelectron spectroscopy showed that although significant amounts of oxygen can be present in the sputtered films, little of the tantalum is fully oxidized to Ta,O,. X-ray photoelectron spectroscopy was also used to show that the oxide layer slowly increases in thickness when heated in air. Finally, KTaO, was identified by XANES on the surface of films exposed to KOH. Once the passive Ta,O, is converted to KTaO,, further oxidation of the underlying films occurs. The mechanism of oxidation of these films; and the unique advantages of each spectroscopic technique are discussed.

InGaP p-n junction mesa diodes were fabricated by wet or dry etching, and the surface recombination velocities (Sv) measured from the size dependence of the current density-voltage characteristics. Within experimental error, the dry etching does not increase the S values, which are in the range 4.4–5.2×104 cm s−1. Subsequent low temperature annealing or plasma exposure did not degrade the surface properties of the mesa diodes, and some improvement was observed with (NH4)2Sx treatment. While the InGaP diodes are relatively insensitive to typical processing steps, comparable AlGaAs p-n junction show much larger changes in surface recombination velocities.

Articles you may be interested inGallium oxide and gadolinium gallium oxide insulators on Si δ -doped GaAs/AlGaAs heterostructures J. Appl. Phys.The role of Gd 2 O 3 is investigated in our previously discovered oxide films of Ga 2 O 3 ͑Gd 2 O 3 ͒ for GaAs surface passivation. Based on the systematic dependence of the dielectric properties of ͑Ga 2 O 3 ͒ 1Ϫx (Gd 2 O 3 ) x on the Gd ͑x͒ content, we showed that pure gallium oxide does not effectively passivate GaAs, and Gd 2 O 3 is a necessary component to stabilize the gallium oxide in the 3 ϩ fully oxidized state due to the electropositive nature of Gd ϩ3 . This gives rise to electrically insulting films of low leakage current and high electrical breakdown strength.

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