New low pressure chemical vapor deposition technique for Ge crystalline thin films

Abstract
A new type of low pressure chemical vapor deposition for Ge thin films was investigated by using a gaseous mixture of GeF4 and Si2H6. At relatively low gas flow ratios of Si2H6/GeF4, etching of Si substrates was observed and the film growth replaced the etching with an increase in the gas flow ratio. The epitaxial growth was achieved at the low temperature of 350–400 °C on a Si(100) substrate, and at a higher temperature region polycrystalline growth took place. The experimental results suggested a major contribution of reductive surface reaction of GeF4 activated by Si2H6 to the Ge film growth.