Buried impurity layers (108, 208), either blanket layers, BILLI structures, or both, are implanted prior to formation of retrograde wells (112, 120, 212, 220) for a CMOS device structure. The blanket buried impurity layer (108) underlies both retrograde wells, while the BILLI structure (208) underlies one retrograde well (212) and overlaps the other (220). Implant doses in excess of 5 x 1014 cm-2 are employed at an energy sufficient to form the buried impurity layer(s) below the expected depth of the retrograde wells unless masked by a protective layer. The buried impurity layers reduce leakage currents and provide intrinsic mobile ion gettering for polished silicon substrates.
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机译：在形成用于CMOS器件结构的逆向阱（112、120、212、220）之前，注入埋入的杂质层（108、208），覆盖层，BILLI结构或两者。毯状掩埋杂质层（108）在两个逆行阱的下面，而BILLI结构（208）在一个逆行阱（212）的下面并且与另一个逆行阱（220）重叠。除非能被保护层所掩盖，否则注入能量的剂量应超过5 x 1014 cm-2，该能量应足以形成低于预期的逆行井深度的埋入杂质层。掩埋的杂质层减少了泄漏电流，并为抛光的硅基板提供了固有的移动性离子吸杂剂。
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