Abstract: Multijunction solar cell structures (100) including high quality epitaxial layers of monocrystalline semiconductor materials that are grown overlying monocrystalline substrates (102) such as large silicon wafers by forming a compliant substrate for growing the monocrystalline layers are disclosed. One way to achieve the formation of a compliant substrate includes first growing an accommodating buffer layer (104) on a silicon wafer. The accommodating buffer (104) layer is a layer of monocrystalline material spaced apart from the silicon wafer by an amorphous interface layer (112) of silicon oxide. The amorphous interface layer (112) dissipates strain and permits the growth of a high quality monocrystalline oxide accommodating buffer layer. Multiple and varied accommodating buffer layers can be used to achieve the monolithic integration of multiple non-lattice matched solar cell junctions.

Abstract: Islands of compound semiconductor material can be formed in silicon wafers by etching wells into the silicon wafer, growing an accommodating layer on the silicon wafer, and then growing a compound semiconductor layer on the accommodating layer. The accommodating layer may be a layer of monocrystalline oxide and an amorphous interface layer of silicon oxide separating the monocrystalline oxide from the silicon wafer. The layer or layers that make up the accommodating layer can be annealed to form a single amorphous layer. A template layer may be grown between the accommodating layer and the monocrystalline compound semiconductor layer. The various layers follow the contours of the wells in the silicon wafer. A polishing step removes the various layers except in the wells, leaving a flat silicon surface having islands of monocrystalline compound semiconductor material separated from the silicon by the accommodating layer, and by the template layer if present.

Abstract: A graded-channel semiconductor device (10) is formed in a pedestal (12). The pedestal (12) is formed on a substrate (11) and improves the electrical characteristics of the device (10) compared to conventional device structures. The pedestal (12) has sides (13) that are bordered by a first dielectric layer (24) to provide electrical isolation. An interconnect structure (90) can be optionally formed in conjunction with the formation of the device (10). The interconnect structure (90) has a plurality of conductors (60,97) that can be used to transport electrical signals across the device (10).

Abstract: A circuit and method protect a transistor (68, 70) from damage when controlling an input signal (V.sub.PROG) that exceeds a gate to channel stress voltage of the transistor. A small, low current protection transistor (64, 66) is serially coupled to the gate electrode of the transistor being protected. The gate of the protection transistor is biased to a voltage (V.sub.P, V.sub.N) of lower magnitude than the input signal to limit the voltage applied to the gate of the protected transistor to a value within the stress voltage of the protected transistor.

Abstract: A graded-channel semiconductor device (10) is formed in a pedestal (12). The pedestal (12) is formed on a substrate (11) and improves the electrical characteristics of the device (10) compared to conventional device structures. The pedestal (12) has sides (13) that are bordered by a first dielectric layer (24) to provide electrical isolation. An interconnect structure (90) can be optionally formed in conjunction with the formation of the device (10). The interconnect structure (90) has a plurality of conductors (60, 97) that can be used to transport electrical signals across the device (10).

Abstract: A multiple output, vertical MOSFET device (11) with improved electrical performance and thermal dissipation is integrated with an additional semiconductor device or semiconductor circuit (18) on a single semiconductor substrate (34). The method of making the vertical MOSFET device (11) involves thinning the semiconductor substrate (34) after fabricating the vertical MOSFET device (11) and the semiconductor circuit (18) to reduce the vertical component of electrical and thermal resistance and to increase the thermal dissipation efficiency. Electrical performance is improved by thinning the semiconductor substrate (34) and by providing a low resistivity, patterned metal buried layer. Thermal management is enhanced by using flip chip bumps (24) to dissipate heat from a top surface (31) of the semiconductor substrate (34) and by using the patterned buried metal layer (26) to dissipate heat from a bottom surface (32) of the semiconductor substrate (34).

Abstract: Insulated gate field effect transistors (10, 70) having process steps for setting the V.sub.T and a device leakage current which are decoupled from the process steps for providing punchthrough protection, thereby lowering a subthreshold swing. In a unilateral transistor (10), a portion (37, 45) of a dopant layer (25, 30) between a source region (48, 51) and a drain region (49, 52) serves as a channel region and sets the V.sub.T and the device leakage current. A halo region (34, 39) contains the source region (48, 51) and sets the punchthrough voltage. In a bilateral transistor (70), both a source region (83, 86) and a drain region (84, 87) are contained within halo regions (75, 74, 79, 81). A portion (76, 82) of a dopant layer (25, 30) sets the V.sub.T and a leakage current, whereas the halo region (75, 79) sets the punchthrough voltage.