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

研究了磷注入4H-SiC（112-0）再结晶速率与杂质浓度的关系。本研究使用的样品为p型4H-SiC（112-0）。磷离子多次注入形成厚度为200 nm的注入层，磷浓度分别为1 × 10^<20>、4 × 10^<20>和1 × 10^<21>/cm^3。在660 ~ 720℃的氩气中，采用黑色碳化硅坩埚和红外图像退火装置对注入样品进行等温退火。P离子注入诱导的4H-SiC（11-20）非晶态层的再结晶速率增加，活化能为3.4 eV，而Ar离子注入诱导的6H-SiC（11-20）和（1-100）非晶态层的再结晶速率也增加。当P浓度从1 × 10^<20> /cm^3增加到1 × 10^<21> /cm^3时，再结晶速率从3.5 nm/min提高到约5nm/min，而Ar注入诱导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界面处的取代杂质的存在促进了再结晶过程的进行。在Al - SiC注入的情况下，也发现了类似的效果。

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.