High energy heavy ion irradiation in semiconductors P.C. Srivastava a, * , S.P. Pandey a , O.P. Sinha a , D.K. Avasthi b , K. Asokan b a Department of Physics, Banaras Hindu University, Varanasi 221 005, India b Nuclear Science Centre, Aruna Asaf Ali Marg, New Delhi 110 067, India Abstract Pd/n-Si and Pd/n-GaAs devices have been irradiated from high energy (100 MeV) heavy ions of Au 7 (gold) and Si 7 (silicon) to study the irradiation eects in these junction devices on semiconductor substrates. The devices have been characterized from I±V and C±V studies for electronic ¯ow characterization. It has been found that the devices become high resistive on the irradiation and the substrates change the conductivity type from n- to p- on the irradiation of ¯uence of 10 12 ±10 13 ions/cm 2 . The change in conductivity type has been understood as a result of creation of deep acceptors on the irradiation. Ó 1999 Elsevier Science B.V. All rights reserved. Keywords: High energy heavy ion; Irradiation; Semiconductors; Diodes; Defects; Conductivity 1. Introduction High energy heavy ion irradiation in materials and in particular the electronic materials has be- come of current interest due to many issues in- volved in the subject. The coming up of Pelletron accelerators and the availability of high energy heavy ion beams for materials science studies has opened the opportunity to study the issues in- volved in the high energy heavy ions implanta- tions. The issues are open both on the fundamental as well as on the applied aspects of the process. The understanding of defect creation and its ki- netics on one side and the application of deep implantation on the other side. Moreover, the study has also the signi®cance for understanding the radiation damage of the electronic devices in the high radiation environment in a reactor labo- ratory or in the outer space. The studies of MeV irradiation have been taken up in electronic devices to study the eect of irra- diation on the performance of the electronic de- vices in high radiation environment. Recently, Yamaguchi and his co-workers [1,2] studied the eect of 1 MeV electrons and 10 MeV proton ir- radiation on n  ±p±p  silicon diodes. An interest- ing feature of carrier removal has been observed in the irradiated diodes. Carrier removal refers to the dramatic reduction in carrier density. The eects of carrier removal upon the device parameters, in particular, the series resistance and saturation current has been discussed in detail. In this report, we present our results of high energy (100 MeV) irradiation of gold (Au 7 ) and Nuclear Instruments and Methods in Physics Research B 156 (1999) 105±109 www.elsevier.nl/locate/nimb * Corresponding author. Fax: +0091-542-317-074; e-mail: pcs@banaras.ernet.in 0168-583X/99/$ ± see front matter Ó 1999 Elsevier Science B.V. All rights reserved. PII: S 0 1 6 8 - 5 8 3 X ( 9 9 ) 0 0 2 5 7 - 8