A process for forming a crystalline deposited film on a substrate surface by preparing the substrate surface on which spaced crystal nuclei are present for forming the crystalline deposited film, forming the crystalline deposited film by introducing an activated species (A) formed decomposition of a compound (SX) containing silicon and a halogen and an activated species (B) formed from a chemical substance for film formation which is chemically mutually reactive with the activated species (A) whereby a mixture is formed between the two activated species to cause a chemical reaction therebetween and thereby affect the formation of the crystalline deposited film. An etching action is thereafter produced on the crystalline deposited film by exposing the film to a gaseous substance (B) capable of effecting an etching action to effect crystal growth in specific face direction.