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(一)引言 除金(Au)以外,作者们还曾详细地介绍过稀有金属钯(Pd)、钆(Gd)、铑(Rh)等在si/SiO_2界面呈现的类似的负电效应。并且讨论过该效应的普遍性及其改善器件表面性质的可能性。近来我们在实验中,又观察到镧(La)也是具有负电效应的杂质,同样能引起MOS结构C-V曲线,包括高频和准静态曲线,沿正栅压方向明显移动。本文介绍的是掺La界面电特性的主要结果。 (二)实验 MOS样品是在电阻率为8—12Ωcm的<111>P型Si单晶片上制成的。Si片是经研磨、SiO_2胶体抛光和化学抛光制成的,厚度约为300μm。在1150℃下HC1和干氧的混合气流中氧化30min,使Si片表面生成厚度约为1200的SiO_2薄膜。去除Si片背面的SiO_2后,在干氮下,从背面扩入La,进而在不同条件(温度、时间、气氛等)下,对
(A) Introduction In addition to gold (Au), the authors also described in detail the similar negative effects of rare metal palladium (Pd), gadolinium (Gd), rhodium and the like on the si / SiO 2 interface. And discusses the universality of the effect and the possibility of improving the surface properties of the device. Recently, we have also observed in experiments that lanthanum (La) is also an impurity with a negative electric effect and can also cause C-V curves of MOS structures, including high-frequency and quasi-static curves, to move significantly in the direction of positive gate voltage. This article describes the main results of doped La interface electrical properties. (B) Experimental MOS samples were made on <111> P-type Si wafers having a resistivity of 8-12 Ωcm. Si chips are ground, SiO 2 colloid and chemical polishing, with a thickness of about 300 μm. The mixture of HC1 and dry oxygen at 1150 ℃ was oxidized for 30 minutes to form a SiO 2 thin film with a thickness of about 1200 on the surface of Si wafer. After removal of the SiO 2 on the back of the Si wafer, La is diffused from the back under dry nitrogen, and then, under different conditions (temperature, time, atmosphere, etc.)