臺灣博碩士論文加值系統

液相沈積法有低溫製程、成本便宜、優良的階梯覆蓋性、選擇性成長、便宜的沈積系統等優點，這些優點使得液相沈積法在IC製程中有多方面的應用。以液相沈積法成長氟氧化矽是一種有潛力去取代傳統成長氟氧化矽方式的方法，但是，不很低的介電常數和不很好的電性等缺點仍然存在於液相沈積法成長的氟氧化矽製程裡。為了改善這些缺點，在本實驗中，掺雜氨水於溶液中，靠著溫差液相沈積法可以成長出高品質和低介電常數的氟氮氧化矽薄膜於矽基板上。
在研究中，當氨水濃度在0.1~0.8 M、沈積溫度在23~40 °C範圍時，成長速率可以被有效地控制在90~550 Å/h。當氨水濃度在0.8 M，沈積溫度改變時，折射係數可以保持在1.431，P-etch速率可以保持在18.3和19.2 Å/s間。最佳的實驗結果是在氨水濃度0.8 M時，氨水濃度高於或低於0.8 M時將會有較差的電特性表現。
從二次離子質譜儀縱深分析得知，我提出一個沈積機制的模型，成長的薄膜是由豐富氮原子累積的膜及較缺乏氮濃度的膜所組成，豐富的氮累積在薄膜和基板介面上的特點展現了良好的電性。
當氨水濃度在0.8 M、沈積溫度在40 °C是最佳條件且薄膜厚度在800 Å可以得到最好的物性、化性、電性表現。薄膜中氟的含量可高達到9.8 %，介電常數可以降低到3.07.

The advantages of LPD method, low temperature process, low cost, conformal growth (good step coverage), selective growth and inexpensive deposition system make the method of LPD versatile in IC fabrication. LPD-SiOF is a potential method to replace traditional method of SiOF deposition. But, some drawbacks, including slightly low dielectric constant and poor performance of J-E relationship, still exist in LPD-SiOF process. In order to improve these shortcomings, with incorporating NH4OH into the LPD solution in this experiment, the SiOF:N film with high quality and low dielectric constant can be grown on Si by the TD-LPD method.
In this study, the growth rate can be controlled well within 90~550 Å/h corresponding to the NH4OH concentration range of 0.1~0.8 M at the temperature range of 23~40 °C. As TD-LPD-SiOF:N film deposited with 0.8 M NH4OH incorporation, the refractive index for can be kept at a constant 1.431 and the P-etch rate can be kept between 18.3 and 19.2 Å/s during the deposition temperature changes.
The best experimental condition is found that incorporating 0.8 M NH4OH will get good results. If the concentration of 0.8 M is higher or lower than 0.8 M, the electrical characteristic will become poor.
A model for TD-LPD-SiOF:N deposition mechanism is proposed. From the analysis of SIMS depth profile, the deposited film can be suggested that it is a combination of N-less LPD-SiOF film and N-rich accumulated interfacial layer. The properties of N-rich accumulated layer at the interface show the least effective oxide charges and lowest leakage current density.
As the thickness of TD-LPD-SiOF:N film is 800 Å, the film has the best electrical characteristic. When the thickness is below or above 800 Å, all the properties become poor. TD-LPD-SiOF:N film deposited at 40 °C with 0.8 M NH4OH incorporation with a thickness of 800 Å has the best physical, chemical, electrical properties. The F content for deposited film can reach 9.8 atom %. The dielectric constant can drop to about 3.07.

CONTENTS I
LIST OF FIGURESIV
ABSTRACT VIII
1. Introduction1
1-1 Background of Fluorinated Silicon Dioxide 1
1-2 Background of TD-LPD-SiOF2
1-3 Motivation of TD-LPD-SiOF:N3
1-4 Mechanisms of TD-LPD-SiOF:N4
1-5 Advantages of LPD5
2. Experiments7
2-1 Deposition System7
2-2 Deposition Procedures8
2-2-1 Si Wafer Cleaning Procedures 8
2-2-2 Preparation of Deposition Solution 8
2-2-3 Film Growth 10
2-3 Fabrication of Metal-oxide-semiconductor Structure 10
2-4 Characteristics 10
2-4-1 Physical and Chemical Properties 10
2-4-2 Electrical Properties 11
3. Results and Discussion 13
3-1 Physical Properties of TD-LPD-SiOF:N Film 13
3-1-1 Deposition Rate and Refractive Index as a Function of Molarity of NH4OH 13
3-1-2 Deposition Rate as a Function of Deposition Temperature 15
3-1-3 Refractive Index as a Function of Deposition Temperature 16
3-1-4 P-etch as a Function of Deposition Temperature 17
3-1-5 SEM View of TD-LPD-SiOF:N Film18
3-2 Chemical properties of TD-LPD-SiOF:N Film18
3-2-1 XPS Analysis for the F Content18
3-2-2 XPS Analysis for the N Content19
3-2-3 AES Survey Scan and Depth Profile20
3-2-4 SIMS Depth Profile 21
3-2-5 Analysis of FTIR Spectra 22
3-3 Model for Deposition Mechanism 23
3-4 Electrical Properties of TD-LPD-SiOF:N Film24
3-4-1 The C-V Measurement of TD-LPD-SiOF:N Films Deposited at 23 °C24
3-4-2 The J-E Relationship of TD-LPD-SiOF:N Films Deposited at 23 °C25
3-4-3 Dielectric Constant of TD-LPD-SiOF:N Film26
3-4-4 The C-V Measurement of TD-LPD-SiOF:N Films Deposited at 40 °C27
3-4-5 The J-E relationship of TD-LPD-SiOF:N Films Deposited at 40 °C28
3-5 Properties of TD-LPD-SiOF:N Films as a Function of Deposition Time30
3-5-1 Thickness as a Function of Deposition Time30
3-5-2 SEM View of the Ultrathin Film30
3-5-3 Dielectric Constant and Flatband Voltage Shift30
3-5-4 The J-E Relationship with Different Thickness31
3-6 Analysis of FTIR Spectra at Various Annealing Temperatures32
3-6-1 Various Annealing Temperatures for 30 min in Ambient N232
3-6-2 Various Annealing Temperatures for 90 min in Ambient N233
4. Conclusions35
FIGURES 37~72
REFERENCES73~81

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