Abstract: A bipolar VLSI process includes masking and patterning, implanting a P+ channel stop (32) and locally oxidizing a P-doped silicon substrate (21) to define a collector region, implanting an N-type collector (43) and diffusing the implants (40, 44). Device emitter, collector and base contact features (64, 66, 68) are photolithographically defined by two openings (54, 56) spaced lengthwise along the collector region. Low resistivity P- and N-type regions (74, 80) are implanted in the substrate in the openings and covered by local oxidation (86, 88). The collector region is preferably formed in a keyhole shape with a wide collector contact feature (66B) and adjoining region 80B and narrow base contact (68B) and emitter (64B) features and intervening region (74B). The substrate (22) is exposed in the emitter and contact features. A single polysilicon layer (94) is deposited, selectively doped and oxidized to form separate base, collector and emitter contacts (94) and a triple diffused NPN transistor (116, 92, 40).

Abstract: A bipolar VLSI process includes masking and patterning, implanting a P+ channel stop and locally oxidizing a lightly P-doped, monolithic silicon substrate to define a long, narrow collector region. An N-type collector is implanted in the collector region. The implants are diffused to form a shallow gradient P-N junction. Then, device features requiring a predetermined spacing and size are photolithographically defined along the length of the collector region. The device features and the collector region are made long enough for the features to readily transect the collector region even if the mask is misaligned. The active transistor and the collector, base and emitter contacts are self-aligned with the collector region so as to take advantage of the noncritical spacing of the preceding steps. A single polysilicon layer used to form base, collector and emitter contacts and a triple diffusion transistor.

Abstract: A solar liquid heating system having a collector receiving solar energy and heating a liquid. A liquid transfer pump moves the heated liquid to a heat transfer tank which heats water. The collector has a plate assembly mounted on a frame. Heat insulated bottoms, sides, and ends surrounded by the frame form an elongated chamber accommodating the plate assembly. The plate assembly has a plurality of side-by-side longitudinal plates. Adjacent plates have generally C-shaped sections that are located about a longitudinal tube for carrying liquid. Adjacent plates have lip and hook inter-connecting structures that cooperate with each other to clamp the tube between the C-shaped sections of the plates. The opposite ends of the tubes are connected to transverse tubular headers. The headers project through resilient grommets mounted on the sides of the frame. The top sides of the plate assembly are coated with black solar energy absorbing material.