沉积气压对纳米晶硅薄膜晶化率与电输运性能的影响

Growth and Property Characterization of B-Doped Nano-Crystalline Si Films

采用热丝化学气相沉积法在不同气压(1～8 Pa)下沉积了p型纳米晶硅薄膜,研究了沉积气压对薄膜晶化率和电输运性能的影响。结果表明,薄膜的晶化率和平均晶粒尺寸随沉积气压升高而增大,而当沉积气压超过6 Pa后,薄膜的晶化率和平均晶粒尺寸会减小。当沉积气压由1 Pa升高到2 Pa时,BH3粒子迅速增多,且吸附方式是化学吸附,因而载流子浓度从8.9×1018cm-3迅速增大到6.252×1020cm-3。此时电导率从1.08 S/cm显著增加到29.5 S/cm,而电导激活能则从95.8meV急剧减小至18.6 meV,这是硼杂质掺杂浓度和薄膜的晶化率迅速增大所致。

The p-type, nano-erystalline hydrogen terminated silicon （nc-Si：H） films were grown by hot wire chemi- cal vapor deposition （HWCVD） on glass substrate. The influence of the deposition conditions, including the pressure, deposition rate, and ratio of HSi4 and H2 flow rates, on the microstmctures and electric properties of the films were evalu- ated. The results show that the pressure and B-doping significantly affect the microstructures and properties of the films. For example, as the pressure increased, the crystallinity and average grain size varied in an increase-decrease mode. As the pressure increased from 1 to 2 Pa, an increased number of BH3 were chemically adsorbed on Si surface, hence the cartier concentration increased from 8.9 x 10TM to 6.252 x 102o era-3. Besides, an increasing boron content also resulted in an increase of the conductivity from 1.08 to 29.5 S/cm and a sharp decrease of the activation energy from 95.8 to 18.6 meV.