公开(公告)号：CA974153A

公开(公告)日：1975-09-09

申请号：CA151676

申请日：1972-09-14

Applicant: IBM

Inventor： KAPLAN LEON H ,  MONTILLO FRANCIS J

IPC: H01L29/78 ,  H01L21/283 ,  H01L21/316 ,  H01L21/336 ,  H01L23/29 ,  H01L29/00

Abstract: 1407222 Making semiconductor devices INTERNATIONAL BUSINESS MACHINES CORP 30 Aug 1972 [27 Sept 1971] 40157/72 Heading H1K An oxide layer is formed on an exposed surface of a silicon body by heating the body in an oxidizing atmosphere that includes, except if desired during the formation of a minor part of the thickness of the oxide layer immediately adjacent the silicon surface, sufficient additive such that at the temperature concerned, the layer, except the said minor part if present, is formed as a liquid and contains the additive as a dopant. The additive may comprise compounds of phosphorus and boron, which inhibit ion migration and which may be derived, for example, by adding POCl 3 or BBr 3 to the oxidizing atmosphere. The concentration of the additive in the oxide may be a few tenths of a mole per cent, but is preferably in the range 1À3 to 2À1 mole per cent. To prevent inversion at the semiconductor surface a minor part of the layer, e.g. 50Š, comprising the oxide without additive, is first formed on the semiconductor, or alternatively on opposite conductivity type additive may be added to compensate for any diffusion of the dopant into the semiconductor. In an example, chemically cleaned P-type Si wafers are preoxidized at 1000‹ C. in dry oxygen flowing at 800 cc. per minute for 4 minutes. The wafers are then exposed to a mixture of oxygen containing 0À8 parts per million POCl 8 for 19- 52 minutes. The resultant mixed SiO 2 -P 2 O 5 layers are formed as a liquid and may be 300- 500Š thick. The method may be used to form the gate insulation of an IGFET.