氮化镓(GaN)器件的自热问题是目前限制其性能的关键因素,在GaN材料上直接生长多晶金刚石改善器件的自热问题成为研究的热点,多晶金刚石距离GaN器件工作有源区近,散热效率高,但多晶金刚石和GaN材料热失配可能会导致GaN电特性衰退.本文采...氮化镓(GaN)器件的自热问题是目前限制其性能的关键因素,在GaN材料上直接生长多晶金刚石改善器件的自热问题成为研究的热点,多晶金刚石距离GaN器件工作有源区近,散热效率高,但多晶金刚石和GaN材料热失配可能会导致GaN电特性衰退.本文采用微波等离子体化学气相沉积法,在2 in (1 in=2.54 cm)Si基GaN材料上生长多晶金刚石.测试结果显示,多晶金刚石整体均匀一致,生长金刚石厚度为9—81 μm,随着多晶金刚石厚度的增大, GaN (002)衍射峰半高宽增量和电性能衰退逐渐增大.通过激光切割和酸法腐蚀,将Si基GaN材料从多晶金刚石上完整地剥离下来.测试结果表明:金刚石高温生长过程中,氢原子对氮化硅外延层缺陷位置有刻蚀作用形成孔洞区域,刻蚀深度可达本征GaN层;在降温过程,孔洞周围形成裂纹区域.剥离下来的Si基GaN材料拉曼特征峰峰位, XRD的(002)衍射峰半高宽以及电性能均恢复到本征状态,说明多晶金刚石与Si基GaN热失配产生应力,引起GaN晶格畸变,导致GaN材料电特性衰退,这种变化具有可恢复性,而非破坏性.展开更多
The Ga_(2)O_(3) films are deposited on the Si and quartz substrates by magnetron sputtering, and annealing. The effects of preparation parameters(such as argon–oxygen flow ratio, sputtering power, sputtering time and...The Ga_(2)O_(3) films are deposited on the Si and quartz substrates by magnetron sputtering, and annealing. The effects of preparation parameters(such as argon–oxygen flow ratio, sputtering power, sputtering time and annealing temperature)on the growth and properties(e.g., surface morphology, crystal structure, optical and electrical properties of the films) are studied by x-ray diffractometer(XRD), scanning electron microscope(SEM), and ultraviolet-visible spectrophotometer(UV-Vis). The results show that the thickness, crystallization quality and surface roughness of the β-Ga_(2)O_(3) film are influenced by those parameters. All β-Ga_(2)O_(3) films show good optical properties. Moreover, the value of bandgap increases with the enlarge of the percentage of oxygen increasing, and decreases with the increase of sputtering power and annealing temperature, indicating that the bandgap is related to the quality of the film and affected by the number of oxygen vacancy defects. The I–V curves show that the Ohmic behavior between metal and β-Ga_(2)O_(3) films is obtained at 900℃. Those results will be helpful for the further research of β-Ga_(2)O_(3) photoelectric semiconductor.展开更多
A suitable contacting scheme for p-(Al)GaN facilitating quick feedback and accurate measurements is proposed in this study.22 nm p^(+)-GaN followed by 2 nm p-In_(0.2)Ga_(0.8)N was grown on p-type layers by metal-organ...A suitable contacting scheme for p-(Al)GaN facilitating quick feedback and accurate measurements is proposed in this study.22 nm p^(+)-GaN followed by 2 nm p-In_(0.2)Ga_(0.8)N was grown on p-type layers by metal-organic chemical vapor deposition.Samples were then cut into squares after annealing and contact electrodes using In balls were put at the corners of the squares.Good linearity between all the electrodes was confirmed inⅠ–Ⅴcurves during Hall measurements even with In metal.Serval samples taken from the same wafer showed small standard deviation of~4%for resistivity,Hall mobility and hole concentration.The influence of contact layer on the electrical characteristics of bulk p-type layers was then investigated by step etching technique using inductively coupled plasma etching and subsequent Hall-effect measurements.Identical values could be obtained consistently when a 28 nm non-conductive layer thickness at the surface was taken into account.Therefore,the procedures for evaluating the electrical properties of GaN-based p-type layers just using In balls proposed in this study are shown to be quick and useful as for the other conventionalⅢ–Ⅴmaterials.展开更多
文摘氮化镓(GaN)器件的自热问题是目前限制其性能的关键因素,在GaN材料上直接生长多晶金刚石改善器件的自热问题成为研究的热点,多晶金刚石距离GaN器件工作有源区近,散热效率高,但多晶金刚石和GaN材料热失配可能会导致GaN电特性衰退.本文采用微波等离子体化学气相沉积法,在2 in (1 in=2.54 cm)Si基GaN材料上生长多晶金刚石.测试结果显示,多晶金刚石整体均匀一致,生长金刚石厚度为9—81 μm,随着多晶金刚石厚度的增大, GaN (002)衍射峰半高宽增量和电性能衰退逐渐增大.通过激光切割和酸法腐蚀,将Si基GaN材料从多晶金刚石上完整地剥离下来.测试结果表明:金刚石高温生长过程中,氢原子对氮化硅外延层缺陷位置有刻蚀作用形成孔洞区域,刻蚀深度可达本征GaN层;在降温过程,孔洞周围形成裂纹区域.剥离下来的Si基GaN材料拉曼特征峰峰位, XRD的(002)衍射峰半高宽以及电性能均恢复到本征状态,说明多晶金刚石与Si基GaN热失配产生应力,引起GaN晶格畸变,导致GaN材料电特性衰退,这种变化具有可恢复性,而非破坏性.
基金Project supported by the Science and Technology Major Project of Shanxi Province,China (Grant No.20181102013)the “1331 Project” Engineering Research Center of Shanxi Province,China (Grant No.PT201801)the Natural Science Foundation of Shanxi Province,China (Grant No.201801D221131)。
文摘The Ga_(2)O_(3) films are deposited on the Si and quartz substrates by magnetron sputtering, and annealing. The effects of preparation parameters(such as argon–oxygen flow ratio, sputtering power, sputtering time and annealing temperature)on the growth and properties(e.g., surface morphology, crystal structure, optical and electrical properties of the films) are studied by x-ray diffractometer(XRD), scanning electron microscope(SEM), and ultraviolet-visible spectrophotometer(UV-Vis). The results show that the thickness, crystallization quality and surface roughness of the β-Ga_(2)O_(3) film are influenced by those parameters. All β-Ga_(2)O_(3) films show good optical properties. Moreover, the value of bandgap increases with the enlarge of the percentage of oxygen increasing, and decreases with the increase of sputtering power and annealing temperature, indicating that the bandgap is related to the quality of the film and affected by the number of oxygen vacancy defects. The I–V curves show that the Ohmic behavior between metal and β-Ga_(2)O_(3) films is obtained at 900℃. Those results will be helpful for the further research of β-Ga_(2)O_(3) photoelectric semiconductor.
基金financially supported by the National Key Research and Development Program of China(2017YFE0131500)the Key Research and Development Program of Guangdong Province(2020B090922001)+2 种基金National Natural Science Foundation of China(61834008,62150710548)Key Research and Development Program of Jiangsu province(BE2020004,BE2021008-1)Guangdong Basic and Applied Basic Research Foundation(2019B1515120091)。
文摘A suitable contacting scheme for p-(Al)GaN facilitating quick feedback and accurate measurements is proposed in this study.22 nm p^(+)-GaN followed by 2 nm p-In_(0.2)Ga_(0.8)N was grown on p-type layers by metal-organic chemical vapor deposition.Samples were then cut into squares after annealing and contact electrodes using In balls were put at the corners of the squares.Good linearity between all the electrodes was confirmed inⅠ–Ⅴcurves during Hall measurements even with In metal.Serval samples taken from the same wafer showed small standard deviation of~4%for resistivity,Hall mobility and hole concentration.The influence of contact layer on the electrical characteristics of bulk p-type layers was then investigated by step etching technique using inductively coupled plasma etching and subsequent Hall-effect measurements.Identical values could be obtained consistently when a 28 nm non-conductive layer thickness at the surface was taken into account.Therefore,the procedures for evaluating the electrical properties of GaN-based p-type layers just using In balls proposed in this study are shown to be quick and useful as for the other conventionalⅢ–Ⅴmaterials.
