Evolution and Elimination of Crystalline Defects Induced by Ge+ Ion Implantation Applied to Shallow p+/n Junction Fabrication and Epitaxy of LPCVD Films
T. E. Hiseh
|關鍵字:||離子佈植;預非晶化;淺接面製作;低壓化學沉積;佈植缺陷消除;固相磊晶成長;Ion implantation;Preamorphization;Shallow junction;LPCVD;Elimination of defects;Solid Phase Epitaxy|
本研究探討低壓化學氣相沈積法所產生的非晶矽薄膜經離子佈植後之固相磊晶成長行為，鍺和矽離子佈植首先被用來將低壓化學氣相沈積法所產生的矽薄膜完全非晶質化，離子佈植並可打散原晶層與非晶層界面的氧化層，在後續的退火過程中，非晶質化的矽以固相磊晶的機制而成長，而得到品質優良的矽磊晶薄膜。感應式耦合電漿(Inductive Couple Plasma)亦被用進行試片表面處理。當使用氮氣進行表面處理時，氮化試片表面可提供空孔來增益原子的擴散速率，固相磊晶的速度得以增加。|
For the fabrication of the shallow p+/n junctions, Ge+ peramorphization was employed to eliminate the channeling effect of BF2+ implantation. This thesis studied the extended defects in Si subjected to various Ge+-preamorphization and BF2+ implantation. The formation and evolution of extended defects depend on the implantation and subsequent annealing conditions. Transmission electron microscopy (TEM) has been employed to study the residual defects and their evolution as well as the methods and mechanisms to eliminate the extended defects are discussed. The extended defects are detrimental to the electrical properties of shallow p+/n junctions. Microwave plasma surface treatment was carried out to form a nitride layer on specimen surface. Such a surface nitridation was found to be effective to reduce the size of end-of-range (EOR) loops. The defect size reduction was more pronounced when the bias voltage was added to the plasma process. Carbon implantation was also employed to annihilate the EOR defects in Ge+-preamorphized Si. It was found that the efficiency of EOR defect removal depends on the Ge+-preamorphized conditions, the location of projected range (Rp) of carbon implantation, and subsequent annealing conditions. Carbon can capture the excess Si interstitials to form SiC complex and reduce the concentration of EOR defects. However, TEM observation revealed the emergence of hairpin dislocations when the dose and accelerating voltage of Ge+ implantation were high. For carbon-implanted specimens, the glide motion of hairpin dislocations would be inhibited by the SiC complexes formed in the vicinity of dislocations. The thesis also discussed the solid phase epitaxy (SPE) of Si thin film prepared by low pressure chemical vapor deposition (LPCVD). In the present work, Ge+ and Si+ ion implantations were utilized to amorphize the LPCVD Si film and mixed the interfacial oxide layer. Ge+ implantation with sufficiently high accelerating voltage and dose amount could break up the oxide layer and the regrowth of amorphous Si could proceed layer by layer during subsequent annealing. An epitaxial layer with superior quality could be obtained. The surface of specimen was also modified by inductive couple plasma (ICP) process. The ICP modification using nitrogen gas was able to accelerate the SPE process.
|Appears in Collections:||Thesis|