METHOD FOR CHEMICAL SURFACE PASSIVATION FOR IN-SITU BULK LIFETIME MEASUREMENT OF SILICON SEMICONDUCTOR MATERIAL

摘要

Minority carrier bulk lifetime maps are accomplished using in-situ mu -PCD measurement techniques on a non-oxydized 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.dm<-3> to about 0.2 mol.dm<-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.