The basic study for LSI-device applications of the single-crystal sapphire films grown by molecular layer epitaxy.

这项研究计划的目的是明确的growth mechanism of molecular-layerepitaxialsingle-crystal insulating-sapphire (<alpha>- al_2_3) films and the methods of applications of thesapphire films to LSI devicesin order to make the performance of the LSI devices higher.Results obtained in this research are asfollows:1. Single-crystal sapphire films are, for the first timesuccessfully grown homoepitaxially on sapphire (0001) and (11^^-02) wafers above [[600 C by themolecular layer epitaxy method which uses alternate transports of alcl_3 vapor and a He 15% o_2 gasmixture (with a pressure of [[5x10_<-3>Pa) to the wafers in a growth chamber. the average growthrates of the sapphire films are observed to be [[0.09nm per cycle of gas transport.2. AlCl （and/or）alcl_2) molecules produced by alcl_3 dissociation would probably compose a monolayer of absorbates与oxygen molecules on a substrate so that each monolayer of al_2_3 is made.3. Theepitaxial growth of sapphire (112^^-0) films on the clean surfaces of single-crystal Nb (100) filmsat [[500 C by the molecular layer epitaxy method is confirmed for the first time. the surface]the Nb film can be covered by the sapphire film with the thickness of several angstroms. This过程is important for fabricating singlejosephson junctions。

The purpose of this research project is to clarify the growth mechanism of molecular-layerepitaxial single-crystal insulating-sapphire (<alpha>-Al_2O_3) films and the methods of applications of the sapphire films to LSI devices, in order to make the performance of the LSI devices higher.Results obtained in this research are as follows: 1. Single-crystal sapphire films are, for the first time, successfully grown homoepitaxially on sapphire (0001) and (11^^-02) wafers above [[600゜C by the molecular layer epitaxy method which uses alternate transports of AlCl_3 vapor and a He 15%O_2 gas mixture (with a pressure of [[5x10_<-3>Pa) to the wafers in a growth chamber. The average growth rates of the sapphire films are observed to be [[0.09nm per cycle of gas transport.2. AlCl (and/or AlCl_2) molecules produced by AlCl_3 dissociation would probably compose a monolayer of absorbates and react with oxygen molecules on a substrate so that each monolayer of Al_2O_3 is made.3. The epitaxial growth of sapphire (112^^-0) films on the clean surfaces of single-crystal Nb (100) films at [[500゜C by the molecular layer epitaxy method is also confirmed for the first time. The surface of the Nb film can be covered by the sapphire film with the thickness of several angstroms. This process is important for fabricating single-crystal Josephson junctions.