Noncontacting laser photocarrier radiometric depth profilometry of harmonically modulated band bending in the space-charge layer at doped Si O 2 - Si interfaces

Laser infrared photocarrier radiometry (PCR) was used with a harmonically modulated low-power laser pump and a superposed dc superband-gap optical bias (a secondary laser beam) to control and monitor the space-charge-layer (SCL) width in oxidized p - Si - Si O 2 and n - Si - Si O 2 interfaces (wafers) exhibiting charged interface-state related band bending. Applying the theory of PCR-SCL dynamics [ A. Mandelis , J. Appl. Phys. 97 , 083508 ( 2005 ) ] to the experiments yielded various transport parameters of the samples as well as depth profiles of the SCL exhibiting complete ( p -type Si) or partial ( n -type Si) band flattening, to a degree controlled by widely different minority-carrier capture cross section at each interface. The uncompensated charge density at the interface was also calculated from the theory.