Surface etching and roughening in integrated processing of thermal oxides
Surface etching and roughening in integrated processing of thermal oxides
复制标题
热氧化物集成加工中的表面蚀刻和粗化
DOI：
10.1116/1.577577
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发表时间：
1991
期刊：
影响因子：
--
通讯作者：
G. Rubloff
中科院分区：
文献类型：
--
作者：
M. Offenberg;M. Liehr;G. Rubloff
利用多室超高真空处理和分析系统研究了集成热氧化工艺，在该系统中，通过超清洁、惰性气氛(净化、干燥的氮气，然后是超高真空)转移晶片，将最终的预清洁过程和热氧化过程整合在一起。当氧化前存在薄的氧化层时，铝栅金属氧化物半导体电容器具有较高的击穿电场(∼12 mV/cm)，而当硅表面最初无氧时，则表现出较低的击穿电场(<；6 mV/cm)。这种对比行为是由于在存在微量浓度(∼100 ppb)的氧气(例如，2Si+O2→2SiO↑)的情况下，在高温下对硅表面进行刻蚀，导致表面粗糙，然后在结构中的粗糙处进行场增强。氧化物表面钝化可防止腐蚀，并确保结构的介电完整性。
A multichamber ultrahigh vacuum processing and analysis system has been used to study integrated thermal oxide processing, in which the final precleaning process and the thermal oxidation process are integrated by employing transfer of the wafers through ultraclean, inert ambients (purified, dry N2 and then ultrahigh vacuum). Al‐gate metal oxide semiconductor capacitors show high breakdown fields (∼12 MV/cm) when a thin oxide passivation layer is present prior to oxidation, but low breakdown fields (< 6MV/cm) when the Si surface is initially oxygen‐free. This contrasting behavior is caused by the etching of Si surfaces which occurs at elevated temperature in the presence of trace concentrations (∼100 ppb) of oxygen (e.g., 2Si+O2→2SiO↑ ), leading to surface roughening and then field enhancement at asperities in the structure. Oxide surface passivation prevents etching and assures the dielectric integrity of the structure.