Electro-chemical mechanical polishing of silicon carbide
Electro-chemical mechanical polishing of silicon carbide
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DOI：
10.1007/s11664-004-0207-6
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发表时间：
2004-05-01
影响因子：
2.1
通讯作者：
Seiler, J
中科院分区：
文献类型：
--
作者：
Li, CH;Bhat, IB;Seiler, J
为了改善碳化硅（SiC）衬底的表面质量，提出了一种新的电化学机械抛光（ECMP）技术。本工作主要针对Si端4 H-SiC（0001）基片进行离轴80 °切割。使用过氧化氢（H2 O2）和硝酸钾（KNO 3）作为电解质，同时使用胶体二氧化硅浆料作为抛光介质以去除氧化物。抛光过程中的电流密度从10 μ A/cm（2）变化到超过20 mA/cm（2）。即使使用高电流密度可以实现高抛光速率，氧化速率和氧化物去除速率也需要适当地平衡，以在抛光后获得光滑的表面。开发了两步ECMP工艺，这使得我们能够分别控制阳极氧化和形成的氧化物的去除。通过控制阳极氧化电流和抛光速率，可以获得最佳的表面形貌。在较高的电流（>20 mA/cm（2））下，最终的表面是粗糙的，而当电流密度在1 mA/cm（2）附近时，获得更光滑的表面。接收晶片，细金刚石浆料（0.1 μ m）抛光晶片，EMCP抛光晶片的表面形貌进行了研究，通过高分辨率原子力显微镜（AFM）。
In an effort to improve the silicon carbide (SiC) substrate surface, a new electro-chemical mechanical polishing (ECMP) technique was developed. This work focused on the Si-terminated 4H-SiC (0001) substrates cut 8degrees off-axis toward . Hydrogen peroxide (H2O2) and potassium nitrate (KNO3) were used as the electrolytes while using colloidal silica slurry as the polishing medium for removal of the oxide. The current density during the polishing was varied from 10 muA/cm(2) to over 20 mA/cm(2). Even though a high polishing rate can be achieved using high current density, the oxidation rate and the oxide removal rate need to be properly balanced to get a smooth surface after polishing. A two-step ECMP process was developed, which allows us to separately control the anodic oxidation and removal of formed oxide. The optimum surface can be achieved by properly controlling the anodic oxidation current as well as the polishing rate. At higher current flow (>20 mA/cm(2)), the final surface was rough, whereas a smoother surface was obtained when the current density was in the vicinity of 1 mA/cm(2). The surface morphology of the as-received wafer, fine diamond slurry (0.1 mum) polished wafer, and EMCP polished wafer were studied by high-resolution atomic force microscopy (AFM).