利用 N2O 與 N2 氣體快速加熱氮化於 PECVD TEOS閘極氧化層及複晶矽氧化層之研究

Abstract

在本論文中，我們利用電漿輔助化學氣相沈積系統於單晶矽及複晶矽薄膜上沈積TEOS氧化層並施以N2O及N2氣體進行快速加熱氮化，藉此分析氧化層之電性與物性的變化。此外，吾人意欲在不同之溫度、氣體與時間的狀況下施以快速退火處理，找出其最佳之退火條件。結果顯示在快速退火的過程中對原始氧化層有緻密化的作用，尤其在N2O的環境下，氮的進入更能大幅提升氧化層的品質與可靠度。亦即，經由N2O氣體快速加熱氮化之氧化層具有較佳之電特性，如較大的崩潰電場、較大的崩潰電荷密度、較低的電子補抓率及較低的漏電流。 因此，TEOS化學氣相沈積氧化層加上N2O快速加熱氮化技術可取代傳統高溫熱氧化層且進一步應用於各式低溫MOS 超大型積體電路製程。

In this thesis, we deposited TEOS oxides by a plasma-enhanced chemical vapor deposition system (PECVD) onto the singlecrystalline and the polycrystalline silicon films with the aid of rapid thermal N2O/N2 annealing to investigate both the electrical and physical properties of the TEOS oxide. In addition, the optimal RTA condition, i.e., temperature, gas and time are studied. It is found that the as-deposited oxides, which are porous and weak, can be densified during the RTA process. Especially for the rapid thermal N2O annealing, nitrogen incorporation largely improves the oxide quality and reliability. In other words, TEOS oxides with RTAN2O exhibit superior electrical characteristics, i.e., a higher dielectric breakdown field, a larger charge-to-breakdown, a lower electron trapping rate and a lower leakage current. As a result, the PECVD TEOS oxide with the RTAN2O can replace the traditional thermal oxides to be applied in various kinds of low-temperature MOS VLSI fabrication. ABSTRACT (in English) ACKNOWLEDGEMENT CONTENTS TABLE CAPTIONS FIGURE CAPTIONS Chapter1 Introduction 1-1 Background 1-2 Motivation 1-3 Organization of The Thesis Chapter 2 The Fundamentals of This Research 2-1 System Configuration 2-1-1 PECVD System 2-1-2 RTA System 2-2 Oxide Integrity Measurement 2-2-1 Basic I-V Characteristics 2-2-2 Measuring Time-Dependent Breakdown Behavior 2-2-3 Mathematics of Reliability Characteristics Chapter 3 The Study of Rapid Thermal N2O/N2 Annealing for PECVD TEOS Gate Oxide 3-1 Introduction 3-2 Experimental Procedures 3-3 Results and Discussion 3-3-1 Measurement of Oxide Thickness 3-3-2 High Frequency and Quasi-Static C-V Characteristics 3-3-3 The Electrical Characteristics of J-E Curves 3-3-4 Characteristics of Breakdown Field 3-3-5 Measurement of Effective Barrier Height 3-3-6 Electron Trapping Characteristics 3-3-7 Characteristics of Charge to Breakdown 3-4 Summary Chapter 4 The Study of Rapid Thermal N2O/N2 Annealing for PECVD TEOS Interpoly Oxide 4-1 Introduction 4-2 Experimental Procedures 4-3 Results and Discussion 4-3-1 Material Analyses 4-3-2 The Electrical Characteristics of J-E Curves 4-3-3 Characteristics of Oxide Breakdown Field 4-3-4 Electron Trapping Characteristics 4-3-5 Characteristics of Charge to Breakdown 4-4 Summary Chapter 5 Conclusions References Vita (in Chinese) Vita (in English)