Non-conventional routes to SiGe:P/Si(100) materials and devices based on -SiH3 and -GeH3 derivatives of phosphorus: synthesis, electrical performance and optical behavior

作者：Xu, Chi^*; Gallagher, J. D.; Sims, P.; Smith, D. J.; Menendez, J.; Kouvetakis, J.

来源：Semiconductor Science and Technology, 2015, 30(4): 045007.

DOI：10.1088/0268-1242/30/4/045007

• n-type Ge
• GeSi photodetectors
• P(SiH3)(3)

Ge-Si based n-type films are synthesized using specially designed hydrides P(SiH3)(3), Ge3H8 and Ge4H10 for potential applications in next-generation CMOS technologies. The films are grown on Ge buffered Si(100) at 340 degrees C using two complementary methods. The first employs a gas-source molecular epitaxy approach using Ge4H10 to produce materials with P doping densities varying from 4 x 10(18) to a 3.5 x 10(19) cm(-3) threshold. These materials are co-doped with Si concentrations ranging from 3 x 10(19) cm(-3) to 3.5%, roughly in proportion with the amount of P(SiH3)(3) used in the reactions. The second approach applies an alternative ultra-high vacuum chemical vapor deposition (UHV-CVD) technique and Ge3H8 in place of Ge4H10 to achieve ultra-high carrier concentrations up to similar to 6x10(19) cm(-3). The Si content in this case is minimal-in the 2-6x10(19) cm(-3) range-indicating that the growth mechanism allows only 'impurity' levels of Si to be incorporated. The active carrier densities in both cases closely reflect the absolute P content, indicating that the P atoms are mostly substitutional. The electron mobilities are significantly higher compared to state-of-the-art prototypes, probably due to superior microstructure and dearth of inactive donors in the lattice. P-I-N diodes fabricated using the P(SiH3)(3) compound show I-V characteristics comparable to state-of-the-art results for Ge-on-Si devices and are virtually undistinguishable from similar diodes doped with the P(SiH3)(3) precursor. These results confirm P(SiH3)(3) as a viable CVD doping source that is practical from a process standpoint and therefore attractive for industrial scale-up.

• 出版日期2015-4