Magyar Tudomanyos Akademia Muszaki Fizikai Kutato Intezete

Semiconductor Physics Laboratory Rt

Semilab Felvezeto Fizikai Lab, Rt

Magyar Tudomanyos Akademia Muszaki Fizikai Kutato Intezet

Gyorgy Ferenczi

Janos Boda

Peter Horvath

Ferenc Toth

Tamas S Horanyi

Jozsef Kiss

Tibor Pavelka

Gyorgy Fule

Zoltan Mirk

Maria Somogyi

Laszlo Dozsa

Gabor Aszodi

Laszlo Benkovics

Katalin Erdelyi

Wolfgang Jantsch

Minority carrier bulk lifetime maps are accomplished using in-situ .mu.-PCD measurement techniques on a non-oxidized Si specimen of either polarity. Surface passivation of the specimen is accomplished chemically, preferably using a solution of iodine in ethanol with a concentration in the range of about 0.02 mol.multidot.dm.sup.-3 to about 0.2 mol.multidot.dm.sup.-3. For n-type specimens, a solution of concentrated alkaline such as ammonia, sodium- and potassium-hydroxide is especially effective. For either type specimens, a solution of HF at about 40% m/m is also effective. Surface passivation according to the present invention reduces surface recombination velocities to 10 cm/second or less. The specimen to be measured is placed in a container of passivation solution such that the specimen surfaces are covered with a solution film of about 1 mm or less. The container preferably is transparent to microwave and laser optical energy, and passivation and measurement can occur simultaneously. A method and apparatus are disclosed.

Method for chemical surface passivation for in-situ bulk lifetime

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.

Method and apparatus for measuring minority carrier lifetime in

Method and apparatus for determining the layer thickness of

Method for the examination of electrically active impurities of

A method for determining charged energy states of a sample of a semiconductor or insulator material by using deep level transient spectroscopy. The method includes the steps of exciting the sample by application of periodical exciting pulses to change the initial charge state, detecting the transient response of the sample when it returns to the thermodynamical balance condition following the termination of each of the excitation pulses, blocking the detection during a blocking period defined as the combined existence of the exciting pulses and of a dead period including the recovery period of the means used for the detection, performing a weighted integration operation on a detected response signal by the application of a symmetrical square wave synchronizing pulse as a weighting function synchronized to the frequency of said exciting pulses, blocking the detection in each of said detecting periods for the duration of a further blocking period which begins in a moment defined between the starting moments of the two exciting pulses immediately preceding and following said detecting period and synchronizing the synchronizing pulses to terminating moments of said dead periods to have a period time which is equal to the period time of said periodical exciting pulses. Apparatus for carrying out the method is also disclosed.

Method for determining charged energy states of semiconductor or

A Deep Level Transient Spectroscopy (DLTS) method in which a high frequency measuring signal is applied continuously on a semiconductor junction, and exciting pulses are generated which are coupled through fast semiconductor switching elements to the junction to alternatively bias the junction in reverse and forward (or slightly reverse) directions. The high frequency measuring signal passed through the junction is evaluated by means of a lock-in amplifier phase-locked with a constant phase angle, independent of the repetition rate of the exciting pulses. The evaluation circuits of the apparatus including the lock-in amplifier are controlled by switching elements driven by control signals generated from the exciting pulses.

Method for deep level transient spectroscopy scanning and apparatus for

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Budapest, Hungary

Gyorgy Ferenczi