The (SiH3)3P hydride is introduced as a practical source for n-doping of group iv semiconductors and as a highly-reactive delivery agent of -(SiH3)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 SiH3Br and (Me3Sn)3P, circumventing the need for toxic and unstable starting materials. As an initial demonstration of its utility we synthesized monosubstituted Me2M-P(SiH3) 2 (M = Al, Ga, In) derivatives of Me3M containing the (SiH3)2P ligand for the first time, in analogy to the known Me2M-P(SiMe3)2 counterparts. A dimeric structure of Me2M-P(SiH3)2 is proposed on the basis of spectroscopic characterizations and quantum chemical simulations. Next, in the context of materials synthesis, the (SiH3)3P compound was used to dope germanium for the first time by building a prototype p++Si(100)/i-Ge/n-Ge photodiode structure. The resultant n-type Ge layers contained active carrier concentrations of 3-4 × 1019 atoms cm-3 as determined by spectroscopic ellipsometry and confirmed by SIMS. Strain analysis using high resolution XRD yielded a Si content of 4 × 1020 atoms cm-3 in agreement with SIMS and within the range expected for incorporating Si3P 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.
ASJC Scopus subject areas
- Inorganic Chemistry