本研究中，首先探討不同基板偏壓及不同氮氣流量比例對反應性濺鍍氮化鉿(HfNx)薄膜材料性質的影響，濺鍍氮化鉿薄膜的方式為使用鉿靶材，在氬氣及氫氣下進行濺鍍，且就材料的電阻率、計量比、密度、晶體結構和化學鍵結進行討論；第二部分，利用特定條件製備金屬鉿(Hf)及氮化鉿薄膜作為閘極電極，製作成HfNx(或Hf)/HfO2/Si MOS電容器，討論MOS電容器經過氮氫混合氣體(90%N2 + 10%H2) 退火前後，整體電性及材料特性的改變。
本實驗利用四點探針來量測薄膜的電阻率；拉塞福背向散射分析儀對薄膜進行組成成份及密度鑑定；使用低掠角X光繞射儀針對薄膜結構及結晶性進行分析；X光光電子能量分析儀則被用來對不同氮氣流量比例的薄膜，進行化學鍵結態分析；利用歐傑電子能譜分析儀對退火前後的MOS結構進行縱深元素分析；另外以電感電容電阻計量儀(HP4284A)進行C-V曲線量測；以微安培計量儀(HP4140B)進行J-V曲線量測。
濺鍍氮化鉿薄膜時，隨基板負偏壓增大，薄膜電阻率會降低，但是，隨氮氣流量比例增大時，薄膜電阻率會增大；由拉塞福背向散射分析儀分析結果，隨氮氣流量比例增大時，薄膜中的氧原子與氮原子所佔比例會增多，薄膜的密度會變小；而由低掠角X光繞射儀可知，隨氮氣流量比例增大時，薄膜會從結晶相改變成接近非晶態的結構；至於X光光電子能量分析可看出，隨氮氣流量比例增大後，Hf的4f5/2和4f7/2峰值會往高能量方向移動。
濺鍍Hf薄膜於矽基材經400oC退火處理，會產生氧化的情況；而濺鍍HfN1.0薄膜與HfN1.3薄膜於矽基材經400oC退火後，材料成分沒有明顯改變。以此三種薄膜為閘極電極材料，製作成HfNx (或Hf)/HfO2/Si MOS電容器在400oC退火後，由低掠角X光繞射儀可知，結晶結構依舊不變；而從歐傑電子縱深能譜分析儀可知，以濺鍍Hf薄膜為閘極電極的MOS電容器，在退火後，氧原子有從表面擴散到矽基材的情形；在C-V曲線及J-V曲線中，顯示氮化鉿薄膜具有相當不錯的熱穩定性；由平帶電壓對等效二氧化矽厚度(VFB vs. EOT)做圖，可得到Hf薄膜、HfN1.0薄膜與HfN1.3薄膜在HfO2上的有效功函數分別為4.08 eV、4.52 eV與4.82 eV。

In this thesis work , HfNx films were prepared by reactive sputtering from a Hf target in an Ar + N2 atmosphere, with different negative substrate biases and nitrogen flow ratios. The resistivity, stoichiometry, density, crystal structure, and bonding configuration of HfNx films were investigated. Subsequently, Hf and HfNx films were applied as the gate electrode in the HfNx(or Hf)/HfO2/Si MOS capacitors. After forming gas (90%N2+10%H2) annealing (FGA), the electrical and material properties of HfNx(or Hf)/HfO2/Si MOS capacitors were discussed.
The film resistivity was obtained by four point probe. Rutherford backscattering spectrometry (RBS) was utilized to examine the stoichiometry and density of the HfNx films. The crystal structure of the HfNx films was identified by grazing incident angle x-ray diffraction (GIAXRD). X-ray photoelectron spectroscopy (XPS) was employed to examine the chemical bonding of the HfNx films. The compositional depth profiles were obtained by Auger electron spectroscopy (AES). For electrical properties of MOS capacitors, the C-V curves were obtained by LCR meter (HP4284A), and picoampere meter (HP4140B) was used to measure the J-V curves.
With the increase of the negative substrate bias, the resistivity of HfNx thin films decreases. However, as the nitrogen flow ratio increases, the resistivity of HfNx thin films increases. In addition, the oxygen and nitrogen contents also increase with the increasing nitrogen flow ratio, and the density of HfNx films decreases. GIAXRD patterns reveal that HfNx films gradually transform from crystalline phase to amorphous structure with increasing nitrogen flow ratio. Furthermore, the binding energy of Hf 4f core-level electrons increases with increasing nitrogen flow ratio.
After annealing at 400oC for 30 min in forming gas, the sputtered Hf thin film oxidizes, but the composition of sputtered HfN1.0 and HfN1.3 thin films remains unchanged. The three films were applied as gate electrodes to form HfNx(or Hf)/HfO2/Si MOS capacitors. From the AES depth profiles, one can find that oxygen atoms diffuse from surface to silicon substrate in the case of Hf/HfO2/Si structure after annealing at 400oC. According to C-V and J-V curves, the HfNx/HfO2/Si MOS capacitors possess good thermal stability. The effective work function values are obtained from the VFB vs. EOT (equivalent oxide thickness) plots. The effective work functions of sputtered Hf, HfN1.0, and HfN1.3 thin films are 4.08 eV, 4.52 eV, and 4.82 eV, respectively.

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