公开(公告)号：US3384793A

公开(公告)日：1968-05-21

申请号：US53260666

申请日：1966-03-08

Applicant: MATSUSHITA ELECTRONICS CORP

Inventor： KYOJI MORIYAMA ,  KOICHIRO SHODA

IPC: H01L21/00 ,  H01L21/22 ,  H01L23/48 ,  H01L29/00 ,  H01L29/73

CPC classification number: H01L29/00 ,  H01L21/00 ,  H01L21/22 ,  H01L23/48 ,  H01L24/05 ,  H01L29/73 ,  H01L2224/04042 ,  H01L2224/48463 ,  H01L2924/12036 ,  H01L2924/00

公开(公告)号：US3384518A

公开(公告)日：1968-05-21

申请号：US49153565

申请日：1965-09-30

Applicant: MATSUSHITA ELECTRONICS CORP

Inventor： KOICHIRO SHODA ,  KYOJI MORIYAMA

IPC: C23C2/14 ,  H01L21/00 ,  H01L21/24

CPC classification number: H01L21/00 ,  C23C2/14 ,  H01L21/24 ,  Y10S148/05 ,  Y10S148/151 ,  Y10S438/955

公开(公告)号：DE1297758B

公开(公告)日：1969-06-19

申请号：DEM0066917

申请日：1965-10-12

Applicant: MATSUSHITA ELECTRONICS CORP

Inventor： KOICHIRO SHODA ,  KYOJI MORIYAMA ,  OAZA YAMADASHIMO

IPC: C23C2/14 ,  H01L21/00 ,  H01L21/24

Abstract: 1,127,213. Semi-conductor devices. MATSUSHITA ELECTRONICS CORP. 28 Sept., 1965 [12 Oct., 1964], No. 41233/65. Heading H1K. [Also in Division C7] To alloy metal contacts to a semi-conductor wafer, the wafer is masked by a suitable surface coating and the masked wafer then immersed in an ultrasonically vibrated bath containing the molten metal. The exposed portions of the masked wafer dissolve in the metal to produce recesses in the wafer surface, and the surfaces of these recesses ultimately become covered with a recrystallized layer of metal-semiconductor alloy. A transistor in which both the ohmic base contact 14 and the rectifying emitter contact 13 have been formed by this method is shown in Fig. 7. An NPN sandwich is first formed by diffusing antimony into the major faces of a P-type germanium wafer of sufficient dimensions to provide several hundred transistors. A silicon oxide coating is then applied to the wafer and each single transistor portion of it has the coating etched away to provide openings 7 and 8, Fig. 4b, for the emitter and base contacts to be formed. These are formed by dipping the coated wafer in ultrasonically vibrated molten lead containing a few per cent of antimony as a dopant for the semi-conductor and a trace (less than 1%) of tin, silver or gold to assist wetting. On removal from the bath excess molten metal is wiped off the wafer and the emitter contacts are subsequently coated with a paste consisting of aluminium or boron powder in a viscous higher alcohol. In a subsequent heat treatment recrystallized P-type region 16 and N-type region 17, Fig. 7, are formed. Since the antimony diffuses more rapidly than the aluminium or boron the original N-type layer 2 of the NPN sandwich spreads to form a continuous base zone beneath the emitter and base contacts 13, 14 and the P-type central zone. 1 of the original NPN sandwich provides a collector zone. The wafer is subsequently cut along line 20 and diced into separate PNP transistors. The oxide layer 4 may be left in position or removed by treatment with acid. A silicon transistor may be made in a similar way except that the original sandwich is a PNP sandwich and it is the base contact which is subsequently doped with boron or aluminium, the resulting structure being an NPN transistor. With silicon, tin is preferred to the lead used with germanium as the principal constituent of the molten alloying metal. Other materials mentioned as possible constituents of the metal bath are indium and arsenic.