Electron beam induced chemical vapor deposition

Abstract

Applicants have invented a new low temperature method (50.degree. C. to 500.degree. C.) to deposit and grow microelectronic thin films using cold cathode electron beams to initiate and sustain both gas phase and surface chemical reactions. The new method uses electron beams generated by glow discharge electron guns. Secondary electrons are emitted from these electron guns following ion and fast neutral bombardment upon cathode surfaces and secondary electrons so formed are accelerated in the cathode sheath. Our method uses the plasma generated electron beams to decompose reactant molecules directly by electron impact and indirectly by the vacuum ultraviolet radiation generated following rare gas electron collisions in the beam region. The reactant molecules can be in the gas phase or adsorbed on substrate surfaces. The electron beams are spatially confined and excite only a localized region above the substrate so that direct plasma bombardment of the substrate is avoided. The film growth and deposition reactions take place on a heated (50.degree. C.-500.degree. C.) substrate therefore with reduced radiation damage at high deposition and growth rates required for in line single wafer processing (>1000.ANG./min). Microelectronic films such as insulators, conductors and semiconductors can be deposited and native films such as oxides and nitrides can be grown with the use of electron beam assisted decomposition of gas molecule reactants.