AVS 53rd International Symposium
    Electronic Materials and Processing Thursday Sessions
       Session EM-ThP

Paper EM-ThP25
Solid Source Phosphorous Doping in Si

Thursday, November 16, 2006, 5:30 pm, Room 3rd Floor Lobby

Session: Electronic Materials and Processing Poster Session
Presenter: G.G. Jernigan, U.S. Naval Research Laboratory
Authors: G.G. Jernigan, U.S. Naval Research Laboratory
P.E. Thompson, U.S. Naval Research Laboratory
Correspondent: Click to Email
Phosphorus doping in Si is being pursed as a possible single spin qubit for quantum computing and as a delta layer for use in a resonant interband tunnel diode. We are using a unique doping source, based on the decomposition of GaP, to produce P in a solid source molecular beam epitaxy machine. This has advantages over the use of phosphine gas decomposition due to the use of lower sample temperatures (< 500 °C) and higher surface coverages (due the absence of hydrogen). We will present a study of the adsorption and desorption of P in the temperature range of 25-800 °C on a Si (100) surface using in vacuo XPS and STM. P is found to adsorb up to one complete monolayer (ML) between 25 and 500 °C and does not form a multilayer. The surface consists of long rows of P dimers separated by vacancy lines. Beginning with 1 ML, P desorbs from Si between 500 and 800 °C. A simple Redhead analysis indicates a second order desorption with an activation energy of ~29 Kcal/mol. Desorption disrupts the P dimer morphology resulting in individual P atoms moving on the surface. STM IV analysis indicates that layer conductivity changes when the dimers break and when P begins to desorb. Compared to a Si surface without P, we find that annealing a surface with a submonolayer of P produces a surface whose step edges are very highly kinked. The relevance of P surface coverage and surface morphology, along with the co-deposition of P and Si, to device applications will be discussed.