Improvements in and relating to Semiconductor Devices

摘要

1,161,351. Semi-conductor devices. INTERNATIONAL BUSINESS MACHINES CORP. 3 March, 1967 [31 March, 1966], No. 10068/67. Heading H1K. The carrier lifetime of a semi-conductor device is reduced by injecting carrier lifetime killers into the device in a non-oxidizing atmosphere after a final oxide layer has been formed on the surface. This is stated to prevent the formation of conductive " pipes " in the device. Semi-conductor devices are produced in P- type silicon slices by successively producing N+, N, P+, P and N-type regions by diffusion in a sealed capsule using silicon powder degenerately doped with arsenic as the source, by epitaxial growth, by diffusion of boron, by a second diffusion of boron, and by diffusion of phosphorus from a POCl 3 source respectively using oxide photo-masking techniques. The last diffusion is followed by an oxidation drivein, a window is opened in the lower face of the wafer, a layer of gold is evaporated on to the exposed surface, the wafer is heated in a nitrogen ambient to diffuse-in the gold, and the wafer is then annealed in a non-oxidizing atmosphere. In a second embodiment the N+, N, P+ and P-type regions are formed as in the first embodiment, a portion of the oxide is removed and gold is diffused-in in an atmosphere of nitrogen or argon, and the final diffusion of N+ type regions is performed in a non-oxidizing atmosphere without any intermediate or subsequent oxidizing step. Electrodes are produced by evaporation of aluminium. The oxide layers used as masks may be produced by heating in dry oxygen, followed by steam, by pyrolytic deposition, or by R.F. sputtering. The first mentioned N+ type regions may be produced by etching a channel and epitaxially depositing N+ type material. Some of the P+ type regions may extend completely through the underlying N-type regions to provide isolation regions in an integrated circuit and this diffusion may also be used to form " underpass " connections.