Consiglio Nazionale delle Ricerche - Istituto per la Microelettronica e Microsistemi (CNR-IMM) Strada VIII n. 5, Zona Industriale, 95121, Catania, Italy.
Beilstein J Nanotechnol. 2013 Apr 8;4:249-54. doi: 10.3762/bjnano.4.26. Print 2013.
The electrical compensation effect of the nitrogen incorporation at the SiO2/4H-SiC (p-type) interface after thermal treatments in ambient N2O is investigated employing both scanning spreading resistance microscopy (SSRM) and scanning capacitance microscopy (SCM). SSRM measurements on p-type 4H-SiC areas selectively exposed to N2O at 1150 °C showed an increased resistance compared to the unexposed ones; this indicates the incorporation of electrically active nitrogen-related donors, which compensate the p-type doping in the SiC surface region. Cross-sectional SCM measurements on SiO2/4H-SiC metal/oxide/semiconductor (MOS) devices highlighted different active carrier concentration profiles in the first 10 nm underneath the insulator-substrate interface depending on the SiO2/4H-SiC roughness. The electrically active incorporated nitrogen produces both a compensation of the acceptors in the substrate and a reduction of the interface state density (D it). This result can be correlated with the 4H-SiC surface configuration. In particular, lower D it values were obtained for a SiO2/SiC interface on faceted SiC than on planar SiC. These effects were explained in terms of the different surface configuration in faceted SiC that enables the simultaneous exposition at the interface of atomic planes with different orientations.
采用扫描扩展电阻显微镜（SSRM）和扫描电容显微镜（SCM）研究了在环境 N2O 中进行热退火后，SiO2/4H-SiC（p 型）界面中掺入氮的电补偿效应。在 1150°C 下选择性地将 N2O 暴露于 p 型 4H-SiC 区域的 SSRM 测量结果表明，与未暴露区域相比，电阻增加；这表明掺入了电活性的与氮相关的施主，从而补偿了 SiC 表面区域的 p 型掺杂。在 SiO2/4H-SiC 金属/氧化物/半导体（MOS）器件上进行的横截面 SCM 测量结果表明，在绝缘体-衬底界面下方的前 10nm 中，根据 SiO2/4H-SiC 的粗糙度，不同的活性载流子浓度分布。电活性掺入的氮不仅补偿了衬底中的受主，还降低了界面态密度（Dit）。这一结果可以与 4H-SiC 的表面结构相关联。特别是，在多面 SiC 上的 SiO2/SiC 界面上获得了比在平面 SiC 上更低的 Dit 值。这些效应可以用多面 SiC 不同的表面结构来解释，这种结构使得不同取向的原子面在界面上同时暴露。
