氮离子注入硅表面的力学性能及其微摩擦磨损行为研究

Nano-mechanics and Micro-tribological Behavior of N^+-implanted Silicon

以单晶硅作为研究对象,选用离子注入剂量分别为5×1014ions/cm2、6×1015ions/cm2和1×1017ions/cm2,注入能量为110 keV的氮离子注入单晶硅片,利用原位纳米力学测试系统对氮离子注入前后单晶硅片的硬度和弹性模量进行测定,在UMT-2型微摩擦磨损试验机上对氮离子注入前后单晶硅片的往复滑动微摩擦磨损性能进行研究.结果表明,氮离子注入后单晶硅片的纳米硬度和弹性模量减小,且注入剂量越大,其降低越明显.氮离子注入后单晶硅片的减摩性能提高,其摩擦系数大幅度降低,在载荷达到一定值后,氮离子注入层被迅速磨穿,摩擦系数迅速增加并产生磨痕.其磨损机制在小载荷下以粘着磨损为主,在大载荷下以材料的微疲劳和微断裂为主.

Single crystal silicon wafer was implanted by nitride ion with 110 keV energy and 5 × 10^14 ions/cm^2, 6 × 10^12 ions/cm^2 and 1 × 10^17 ions/cm^2 doses, respectively. The changes of mechanical properties, such as hardness and elastic modulus of silicon implanted by nitride ion were studied on the in-situ nano-mechanical testing system. The micro sliding tests on silicon wafer and the N^＋ -implanted silicon wafer were tested on a UMT-2 Micro-tribometer, which attempted to evaluate the wear resistance of N^＋ -implanted silicon wafer and to investigate its micro tribological properties, such as friction coefficient and lastic modulus decreased for the N^＋ implanted silicon wear width. The results show that the nano-hardness and ewafer. The more dose the silicon wafer was implanted, the more its nano-hardness and elastic modulus decreased. Friction-reducing effect of the N^＋ implanted silicon wafer improved and its coefficient of friction decreased to a great extent. When the load reached to a certain value, the N^＋ implantation thin layer was quickly worn out and the coefficient of friction increased sharply and the worn trace occurred on the silicon wafer surface. Adhesive wear was the main mechanism at light loads and fatigue and micro fracture were the main mechanism at high loads.