Ion Implantation Profile Optimization for Thermal Drift Suppression in MEMS
Dual-implant boron-phosphorus profiles achieve zero-crossing TCR at 3.5e19 cm^-3, suppressing piezoresistive thermal drift to 12 ppm/K.
Atomic Lattice Damage
Structural Degradation
Physical displacement of atoms from their equilibrium positions in a crystalline solid creates a state of disorder. This condition, known as atomic lattice damage, arises primarily during ion implantation or high-energy particle irradiation in semiconductor manufacturing where the kinetic energy of the incoming species exceeds the displacement threshold of the target material. The disruption breaks the periodic symmetry of the silicon crystal and leads to the formation of point defects such as vacancies and interstitials.
These defects alter the local electrical and mechanical properties of the substrate.
Collision Effect
Collision cascades generated by accelerated ions transfer kinetic energy to target nuclei. This forces them into non-lattice sites.
Metrological Verification
Rutherford backscattering spectrometry provides a quantitative measure of the displaced atom density relative to the virgin crystal. Channelling experiments yield a damage profile that correlates depth with the concentration of scattering centres. This verification ensures that the substrate can support active carrier transport after annealing.
Recovery Boundary
Solid phase epitaxial regrowth facilitates the restoration of the crystal structure when heat is applied. Thermal energy allows atoms to migrate back to stable sites. If the initial atomic lattice damage is too extensive, residual dislocations or stacking faults persist.
These permanent flaws degrade device leakage characteristics and cannot be removed by standard processing.