Preliminary EM6 Modifications for in situ Chemical Vapor Deposition

Abstract

An AEI EM6 electron microscope is being modified for in situ chemical vapor deposition. The objective is to observe the nucleation and growth kinetics and structure of silicon deposited by SiH4 gas pyrolysis on substrates of sapphire (single crystal α-Al2O3).An Edwards DCB2 thermoelectrically cooled baffle has been installed using a simple adapter which permitted attachment without drilling or cutting of the EM6 frame or vacuum system. Prior to installation the measured contamination rate was 240Å/min; afterward the contamination rate was less than 100 Å/min.An auxiliary pumping system is mounted to the left rear of the column and attached by a special stainless steel flexible bellows to the pumping port at the rear of the specimen chamber. The auxiliary system has an ultimate presure <1 × 10-6 torr, but the measured pressure in the specimen chamber was no better than 1 × 10-5 torr, due primarily to the high outgassing rate of the beam deflector coil immediately above the specimen chamber.