CO/sub 2/ laser processing of diffusion induced lattice imperfections in silicon: Experiment and theory
The high-temperature diffusion of phosphorus into crystalline silicon causes the formation of electrically inactive phosphorus-rich precipitates near the surface. These precipitates decrease the carrier lifetime and mobility in the diffused layer, and thus lead to less than optimal diode characteristics of electrical junctions formed by diffusion of phosphorus into a p-type substrate. We show that the free-carrier absorption of a CO/sub 2/ laser pulse can be used to completely dissolve the precipitates and remove dislocations in the diffused layer. Furthermore, we find that there are distinct advantages in depositing the pulse energy by way of free-carrier transitions, since the energy can be preferentially deposited in either confined doped layers or diffusion wells that are surrounded by lightly doped material. Our transmission electron microscopy results show that the annealing of the extended lattice defects is caused by melting of the near-surface region and subsequent liquid-phase epitaxial regrowth. Van der Pauw measurements are used to study the carrier concentration, mobility, and sheet resistivity of the samples before and after laser irradiation. The results of the electrical measurements show that there is a large increase in the carrier concentrations and a corresponding drop in the sheet resistivities of the laser irradiated samples. Using a Fourier transform
- Research Organization:
- Sandia National Laboratories, Livermore, California 94550
- OSTI ID:
- 6230065
- Journal Information:
- J. Appl. Phys.; (United States), Journal Name: J. Appl. Phys.; (United States) Vol. 62:7; ISSN JAPIA
- Country of Publication:
- United States
- Language:
- English
Similar Records
Laser annealing of diffusion-induced imperfections in silicon
Pulsed CO sub 2 laser processing of thin ion-implanted silicon layers
Related Subjects
360603* -- Materials-- Properties
ABSORPTION SPECTRA
ATOM TRANSPORT
CARBON DIOXIDE LASERS
CARRIER DENSITY
CARRIER LIFETIME
CRYSTAL DEFECTS
CRYSTAL DOPING
CRYSTAL STRUCTURE
DATA
DIFFUSION
ELEMENTS
EXPERIMENTAL DATA
GAS LASERS
INFORMATION
LASERS
LIFETIME
LIGHT TRANSMISSION
NEUTRAL-PARTICLE TRANSPORT
NONMETALS
NUMERICAL DATA
OPTICAL PROPERTIES
PHOSPHORUS
PHYSICAL PROPERTIES
PHYSICAL RADIATION EFFECTS
PRECIPITATION
RADIATION EFFECTS
RADIATION TRANSPORT
REFLECTIVITY
SEMIMETALS
SEPARATION PROCESSES
SILICON
SPECTRA
SURFACE PROPERTIES
THEORETICAL DATA