Practical routes to (SiH_3)_3P: Applications in group IV semiconductor activation and in group III-V molecular synthesis

摘要

The (SiH_3)_3P hydride is introduced as a practical source for n-doping of group iv semiconductors and as a highly-reactive delivery agent of -(SiH_3)_2P functionalities in exploratory synthesis. In contrast to earlier methods, the compound is produced here in high purity quantitative yields via a new single-step method based on reactions of SiH_3Br and (Me_3Sn)_3P, circumventing the need for toxic and unstable starting materials. As an initial demonstration of its utility we synthesized monosubstituted Me_2M-P(SiH_3) _2 (M = Al, Ga, In) derivatives of Me_3M containing the (SiH_3)_2P ligand for the first time, in analogy to the known Me_2M-P(SiMe_3)_2 counterparts. A dimeric structure of Me_2M-P(SiH_3)_2 is proposed on the basis of spectroscopic characterizations and quantum chemical simulations. Next, in the context of materials synthesis, the (SiH_3)_3P compound was used to dope germanium for the first time by building a prototype p~(++)Si(100)/i-Ge-Ge photodiode structure. The resultant n-type Ge layers contained active carrier concentrations of 3-4 × 10~(19) atoms cm~(-3) as determined by spectroscopic ellipsometry and confirmed by SIMS. Strain analysis using high resolution XRD yielded a Si content of 4 × 10~(20) atoms cm~(-3) in agreement with SIMS and within the range expected for incorporating Si_3P type units into the diamond cubic Ge matrix. Extensive characterizations for structure, morphology and crystallinity indicate that the Si co-dopant plays essentially a passive role and does not compromise the device quality of the host material nor does it fundamentally alter its optical properties.