| Summary: | 碩士 === 國立成功大學 === 微電子工程研究所碩博士班 === 93 === Abstract
In this thesis, the materials characteristics of zirconium (Zr) doped zinc oxide (ZnO) films and their contacts on p-type GaN were investigated. The transparent and conductive ZnO films were doped with Zr atoms at concentrations of 8.2, 10 and 15 wt%, respectively. Sequentially, the contact properties of the optimum transparent and conductive ZZO films contacted on p-type GaN were conducted from a transmittance line model (TLM).
These ZnO films doped at various Zr atoms were deposited on sapphire (0001) substrates using a cosputtering system employed ZnO and Zr targets. Post-annealing treatments were also carried out to improve the associated optical properties in ultraviolet region and electrical characteristics of these ZZO films. A ZZO film possessed superior optical and electrical properties was achieved at a doped concentration of Zr atoms reaching 8.2 wt%. After annealing at 1100 oC for 1 min. under nitrogen ambience, the resistivity and carrier concentration of this ZZO films were improved to 2.21 × 10-3 Ω cm and 3.26 × 1020 cm-3, respectively. Meanwhile, a superior average transmittance higher than 85 % in visible region was also obtained. Furthermore, the absorption edge of this annealed ZZO films (Zr: 8.2 wt%) was found to blue-shift attributed to Burstein-Moss effect. the transmittance at 380 nm in ultraviolet region was therefore enhanced from 10.7 % (without post-annealing treatment) to 86.6 %.
As a result of producing dissolution of GaN for annealing above high temperature (>900oC), the better annealing condition for transmittance line model devices is annealing treatment at 900oC for 1 minute in pure N2. The electrodes of TLM devices which were made under above conditions would have lower specific resistances. We measured the characteristic of ohmic contact from the sample of p-GaN, the specific contact resistances ρC = 3.80×10-4Ω-cm2.
|
|---|
