VAPOR PHASE EPITAXY MANUFACTURING METHOD

摘要

PURPOSE:To obtain the double-layer epitaxial layer having a steep carrier profile by working out the supply delay time of a doping gas of the second layer by a specified formula. CONSTITUTION:Two kinds of doping gases D1 and D2 of the same kind of doping element which have different concentration are supplied in order together with a raw material gas and a double epitaxial layer such as n<+>/n or p<+>/p is formed. In such gas-phase epitaxial growth, after stopping a supply of the doping gas D1 for the first layer, a delay time Tf till the start of supplying the doping gas D2 for the second layer is determined by a formula; Tf=K1lnn+ K2 wherein (n) is a carrier concentration of the second layer. K1 and K2 in the formular are constants and K1 and K2 have been worked out regarding a certain device. At first, an n<+> (or p<+>) layer is grown by using the first layer doping gas D1 which is stopped when a predetermined film thickness is attained. The supply of the material gas is continued and the supply of the second layer doping gas D2 is started after Tf.