The INFOS 81 Conference on Insulating Films on Semiconductors was held at the University of Erlangen-NUrnberg in Erlangen from 27 to 29 April 1981. This conference was a sequel to the first conference INFOS 79 held in Durham. INFOS 81 attracted 170 participants from universities, research institutes and industry. Attendants were registered from 15 nations. The biannual topical conference series will be continued by INFOS 83 to be held in Eindhoven, The Netherlands, in April 1983. The conference proceedings include all the invited (Y) and contrlDUtea (42) papers presented at the meeting. The topics range from the basic physical understanding of the properties of insulating films and their interface to semiconductors to the discussion of stability and dielectric strength as well as growing and deposition techniques which are relevant for technical applications. Strong emphasis was given to the semiconductor silicon and its native oxide; however, sessions on compound semiconductors and other insulating films also raised strong interest. The proceedings survey the present state of our understanding of the system of insulating films on semiconductors. As a new aspect of the topic, the properties of semiconductors deposited and laser processed on insulating films was in cluded for the first time.