活性離子蝕刻與電子迴旋共振蝕刻在矽基材上所造成的蝕刻破壞之研究

Abstract

在本論文中, 我們探討了在活性離子蝕刻過的矽基座表面成長的氧矽介電 層之特性, 並比較在氧化氮的氣氛中所成長之氧化矽與傳統的乾式氧化所 成長的氧化矽的特性. 在介面分析方面, 原子力顯微鏡, 光譜分析儀, 高 解析度穿透式電子顯微鏡被用來探討氧化矽及矽基座介面粗糙程度. 在電 性分析方面, 介電層電場崩潰特性被用來評估氧化矽的特性優劣. 對成長 在活性離子蝕刻過的矽基座表面的80埃厚的氧化矽而言,在氧化氮的氣氛 中所成長之氧化矽與傳統的乾式氧化所成長的氧化矽相較, 具有較平整的 氧化矽及矽基座介面, 並且具有較佳的場崩潰特性.此外, 蝕刻條件以及 蝕刻後續處理對氧化矽及矽基座介面粗糙程度, 及介電層電場崩潰特性也 被探討.另外, 利用電子迴旋共振蝕刻複晶矽亦被研究. 使用含氯或溴化 氫的氣體所產生的電子迴旋共振高密度電漿, 可以得到良好複晶矽對氧化 矽選擇比. 但是, 此高密度電漿仍將對介電氧化層與氧化矽及矽基座介 面, 甚至是氧化層之下的矽基座造成損壞. 在本論文中, 利用金屬/矽基 座蕭基接面的電流電壓特性, 及深階暫態電容特性來探討此高密度電漿所 造成的破壞. 而此破壞將可由900。高溫退火處理加以改善. In this thesis, we study the properties of thin oxides thermally grown on reactive-ion-etched (RIE) silicon substrates in N2O and diluted O2 ambient. The interface microroughness is strongly dependent on the RIE conditions and the post etching treatments. Furthermore, using the after-treatment-chamber (ATC) process, CF4 addition in the O2 plasma can further improve the time-zero-to-dielectric-breakdown (TZDB) characteristics of the thin oxides as compared with pure O2 plasma. As compared with pure oxides grown on the etched silicon in dry oxygen, N2O-grown oxides exhibit significantly stronger immunity to the RIE- induced damages. N2O oxidation of the etched specimens treated with a proper after-treatment- chamber (ATC) process result in the best electrical properties, including TZDB and time- dependent-dielectric-breakdown (TDDB) characteristics. In addition, the SiO2 and silicon substrate damages produced by Cl2- and HBr-based electron cyclotron resonance (ECR) plasma etching after the poly-Si overetch has been investigated. The current-voltage (I-V) characteristics of the Schotthy barrier diodes are formed on the plasma damaged silicon substrates to characterize the influence of the plasma exposure.