Determination of interfacial states in solid heterostructures using a variable-energy positron beam

Patent · 06 April 1993

OSTI ID:6023321

Asokakumar, P P.V.; Lynn, K G

A method and means is provided for characterizing interfacial electron states in solid heterostructures using a variable energy positron beam to probe the solid heterostructure. The method includes the steps of directing a positron beam having a selected energy level at a point on the solid heterostructure so that the positron beam penetrates into the solid heterostructure and causes positrons to collide with the electrons at an interface of the solid heterostructure. The number and energy of gamma rays emitted from the solid heterostructure as a result of the annihilation of positrons with electrons at the interface are detected. The data is quantified as a function of the Doppler broadening of the photopeak about the 511 keV line created by the annihilation of the positrons and electrons at the interface, preferably, as an S-parameter function; and a normalized S-parameter function of the data is obtained. The function of data obtained is compared with a corresponding function of the Doppler broadening of the annihilation photopeak about 511 keV for a positron beam having a second energy level directed at the same material making up a portion of the solid heterostructure. The comparison of these functions facilitates characterization of the interfacial states of electrons in the solid heterostructure at points corresponding to the penetration of positrons having the particular energy levels into the interface of the solid heterostructure. Accordingly, the invention provides a variable-energy non-destructive probe of solid heterostructures, such as SiO[sub 2]/Si, MOS or other semiconductor devices.

• DOE Contract Number: AC02-76CH00016
• Assignee: Associated Universities, Inc., Washington, DC (United States)
• Patent Number(s): A; US 5200619
• Application Number: PPN: US 7-770891
• OSTI ID: 6023321
• Country of Publication: United States
• Language: English

Related Subjects

665100* -- Nuclear Techniques in Condensed Matter Physics -- (1992-)
75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
ANNIHILATION
BASIC INTERACTIONS
BEAMS
DOPPLER EFFECT
ELECTROMAGNETIC INTERACTIONS
ELECTROMAGNETIC RADIATION
ELECTRONIC STRUCTURE
ELECTRONS
ELEMENTARY PARTICLES
ENERGY LEVELS
FERMIONS
GAMMA RADIATION
HETEROJUNCTIONS
INTERACTIONS
INTERFACES
IONIZING RADIATIONS
JUNCTIONS
LEPTON BEAMS
LEPTONS
PARTICLE BEAMS
PARTICLE INTERACTIONS
POSITRON BEAMS
RADIATIONS
SEMICONDUCTOR DEVICES
SEMICONDUCTOR JUNCTIONS