Semilab Felvezto Fizikai Laboratorium Rt

Semilab Felvezeto Fizikai Lab, Rt

Tibor Pavelka

Gyorgy Ferenczi

Peter Horvath

Janos Boda

Zoltan Mirk

The invention relates to a method and arrangement for passivating the surface of semiconductor samples in which, simultaneously to passivation, the life-time of free carriers is also determined by illuminating the semiconductor sample by a light pulse of higher energy than the forbidden band of the material, and the time function of the resistance change occurring in the semiconductor as a result of illumination is measured advantageously by a microwave reflectometer, and the life-time of carriers is determined as the characteristic time constant of the process. The essence of the method lies in that, the surface part of the semiconductor sample to be measured is continuously electrically charged. The arrangement comprises a microwave reflectometer ( ), a signal processing unit ( ), and a laser light source ( ) illuminating the semiconductor sample ( ). The surface of the semiconductor sample ( ) charged by ions generated by corona generators ( ) simultaneously with the measurement.

Surface passivation method and arrangement for measuring the lifetime of minority carriers in semiconductors

A contactless apparatus for measuring contaminants in a semiconductor specimen (24) includes a tunable microwave generator (26) coupled by a coaxial cable (36) to a tuned narrowband microstrip antenna (38) that defines a through hole (72). The antenna is placed in near field relationship to the specimen to direct microwave energy toward a first specimen surface (44). This proximity provides a substantially more powerful microwave field than prior art systems, and the specimen comprises an impedance termination for the microwave path that includes the microwave generator and antenna, thereby rendering system measurements substantially immune to mechanical vibration of the specimen. A pulsed laser (42) directs optical energy through the antenna through hole toward the first specimen surface (44). The optical energy generates minority carriers within the specimen that begin to recombine upon cessation of each pulse. Minority lifetime decay affects microwave energy reflecting from freed holes and electrons in the specimen, which energy is coupled from the antenna to a detector (46) and preferably a computer system (48) that controls the system and provides signal processing of the detector output.

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Budapest, Hungary

Tibor Pavelka