Feldeffekttransistor

摘要

1,073,135. Semi-conductor devices. MOTOROLA Inc. Oct. 21, 1964 [Nov. 6, 1963], No. 42930/64. Heading H1K. A current limiter comprises a junction gate field-effect structure, having a channel comprising two sequential sections with different electrical characteristics, and having the source and gate regions connected to a common electrode. The device operates as if it comprises two field-effect transistors connected in series and having their gates connected together and connected to the extreme source region, Fig. 2 (not shown). The difference in characteristics of the channel sections ensures that one pinchesoff before the other, and this is achieved by providing one section of the channel with a gate region on both sides while the other section has a gate region on one side only. As shown, Fig. 4, a layer of N-type silicon doped with phosphorus is epitaxially deposited from the vapour phase on a P-type silicon substrate 11. Boron is diffused into the N-type layer, using a silicon dioxide mask, to form annular P+ type regions 23 and 47. Phosphorus is diffused into the layer to form annular N+ type source and drain regions 14 and 41. The oxide layer is reformed and parts are removed to expose the drain region 41 and an annular region extending outwardly from the centre of the channel region. Aluminium is vapour deposited over the surface and removed from those areas protected by the oxide. The aluminium is then alloyed to the surface, the outer portion 20 forming ohmic contacts with region 23 and source 14 and forming a regrown P-type gate region 17, while the inner annular portion makes ohmic contact with drain region 41. This drain contact is extended over oxide layer 44 by applying a metal layer 43, and a contact 19 is simultaneously applied to the lower face of the substrate. Contact (19) is bonded to a member (46) which is connected to one lead of a glass envelope, Fig. 6 (not shown), the other lead of which is connected via an S-shaped member to drain contact (43). A plurality of devices may be simultaneously produced in a single wafer.