Studies on the SEM examination of un-coated non-conductive specimens prepared by plasma-ion shower method

The plasma-ion shower method is an effective technique for the SEM examination of un-coated electrically non-conductive specimens. However, milling damage to specimens cannot be prevented by the irradiation method using accelerated Ar ion beam. We, therefore, applied positive ions obtained by plasma discharge to the specimen like a shower by reflecting from the target electrode surface. He, N2 or Ar was used as the environmental gas, and the discharge voltage was varied from 200 V to 1000 V. At 5 kV to 25 kV of SEM accelerating voltage, it was possible to visualize un-coated hard and soft biological and inorganic specimens under 5 mA or 10 mA of discharge current and 5 min or 10 min of processing time.