Contactless Characterization of Semiconductors Using Laser-Induced Surface Photo-Charge Voltage Measurements.
Abstract
A new technique to evaluate the electrical properties of semiconductor wafers and devices using surface photo-charge voltage (SPCV) measurements is presented. SPCV measures the change in the surface electrical charge induced by a chopped laser light whose photon energy exceeds the band gap energy of the semiconductor sample. This charge is measured capacitatively, thus SPCV measurements do not require the fabrication of metal contacts. In photocharge voltage spectroscopy measurements, the SPCV is measured as a function of the energy of a subband gap monochromatic steady-state illumination, and its derivative spectrum is associated with the density of surface states. A qualitative analysis of the proposed measurement is presented along with experimental results performed on gallium arsenide samples passivated with a thin zinc selenide film of variable thickness. The proposed technique is completely contactless, and it can be used as an in-line nondestructive characterization of semiconductor wafers during the various stages of integrated circuits fabrication. jg
Document Details
- Document Type
- Technical Report
- Publication Date
- Jan 01, 1995
- Accession Number
- ADA293618
Entities
People
- A. Abbate
- F. Palma
- G. Masini
- O. Ivanov
- R. Rencibia
Organizations
- United States Army Armament Research, Development and Engineering Center