Investigation of impurity effect on re-crystallization process in heavily implanted silicon carbide

我们研究了磷注入4H-碳化硅(112-0)的再结晶速率与杂质浓度的关系。本研究所用的样品为p型4H-碳化硅(112-0)。磷离子的多次注入形成了厚度为200 nm、磷浓度分别为1×10~(-1)、4×10~(-2)和1×10~(-2)/cm~(-3)的注入层。在Ar气流中，注入样品在660~720℃的温度范围内，用带黑色碳化硅坩埚的红外图像退火炉进行了等温退火。当激活能为3.4 eV时，4H-SiC(11-20)中P离子注入非晶层的再结晶速率增加，而6H-SiC(11-20)和(1-100)中Ar离子注入非晶层的再结晶速率也增加。当P浓度从1×10~(-2)增加到1×10~(-2)/cm~(-3)时，再结晶速率从3.5提高到约5 nm/min，而Ar注入非晶层的再结晶速率为1.5 nm/min。结果表明，在再结晶过程中，A/C界面处的代位杂质的存在促进了再结晶过程。对于Al注入碳化硅的情况也发现了类似的效应。

We investigated that the impurity concentration dependence of the recrystallization rate of the phosphorus implanted 4H-SiC(112-0). Samples used in the present study were p-type 4H-SiC(112-0). The phosphorus ions were multiply implanted to form the implantation layer with the thickness of 200 nm and the phosphorus concentration of 1 x 10^<20>, 4 x 10^<20>, and 1 x 10^<21>/cm^3, respectively. The isothermal annealing of the implanted samples were performed at the temperature range from 660 to 720 ℃ in Ar gas flow using an infrared image annealer with a black SiC crucible. The recrystallization rate of the P ion implantation-induced amorphous layer in 4H-SiC(11-20) increases with an activation energy of 3.4 eV as well as the case of the Ar ion implantation-induced amorphous layer in 6H-SiC(11-20) and (1-100). As the P concentration is increased from 1 x 10^<20> to 1 x 10^<21> /cm^3, the recrystallization rate is enhanced from 3.5 to about 5nm/min, while the recrystallization rate for Ar implantation-induced amorphous layer was 1.5 nm/min. It is suggested that the recrysallizatioin process is enhanced by the presence of the substitutional impurity at the a/c interface during the recrystallization. The similar effect is identified for the case of the implanted of Al to SiC.