| Summary: | 碩士 === 國立雲林科技大學 === 電子與資訊工程研究所碩士班 === 92 === In this dissertation, we will discuss different conditions of Ni film thickness and annealing temperatures for p-type GaN to find out the best way to increase the hole concentration and improve electrical characteristic. We chose Ni because it has been widely used in hydrogen storage alloys to increase the hydrogen desorption rate, and use several kinds of instruments to analyze the optic and electrical properties, include of photoluminescence (PL), second ion mass spectrometry (SIMS), inductively coupled plasma (ICP), Hall effect measurement and I-V measurement.
Study the Ni catalysis of 2, 10, 20 and 50 nm thick under various annealing temperatures to reduce H concentration in p-type GaN layer. In these results, the I-V curves show higher electrical characteristic than convention process method, the highest hole concentration of 3.25×1018 cm-3 with the mobility of 0.922 cm2/Vs was obtained at the annealing temperature of 600℃ (approximately 2 nm thick). This hole concentration is one order of magnitude higher than that of the sample without the Ni
film at this annealing temperature, and then, employ photoluminescence to define meaning of several peaks, Mg peak location ranging from 2.75 to 2.9 eV (450~425 nm), we discover that Mg peak changed evident when annealed in the temperature range of 200℃ to 800℃ with Ni catalytic. So we apply SIMS to analyze the internal elements of p-type GaN layer further.
We analyze the number of H, O and Ni in Mg-doped GaN layer after treated with different thickness of Ni films annealing in nitrogen atmospheres in the temperature range of 200℃, 500℃, 700℃ and 800℃ for 10 min. The results indicated that the H concentration decreased and O concentration increased when samples annealed with and without Ni at high temperature (>500℃), and the H and O concentration increased and collected in shallow layer. We infer that Ni diffused in Mg-doped GaN layer will influence the optic and electrical property of as-grown Mg-doped GaN.
In this dissertation, we mainly aimed at the electrical properties of Mg-doped GaN with and without Ni film at different annealing temperatures, and study the electrical characteristic when the Ni compound materials in shallow layer of p-type GaN via ICP instrument.
|
|---|
