Abstract: A buried channel lateral quasi-unipolar transistor having low flicker or 1/f noise has a bulk region that forms the base of the buried quasi-unipolar transistor. A drain region is implanted into the bulk region to form a drain/collector. A source region is placed at a distance from the drain region and is implanted in the bulk region to form a source/emitter. A channel layer is implanted in the bulk region between the source region and the drain region to provide a low resistivity conduction channel between the drain/collector and the source/emitter. A gate oxide is placed on the surface of the semiconductor substrate immediately above the channel layer. Then a gate electrode of a conductive material such as polycrystalline silicon doped to with a material having a conductivity opposite that of the source/drain deposited on the gate oxide above the channel region. A biasing voltage source connected between the gate electrode and the bulk region to lower a built-in voltage of the quasi-unipolar transistor.
Type:
Grant
Filed:
December 28, 1998
Date of Patent:
June 12, 2001
Assignee:
Industrial Technology Research Institute
Abstract: A stacked capacitor that has a large capacitance per unit area (Co), very low voltage coefficient (Kv), and an acceptable parasitic capacitance factor (Kp) is described that uses only one polysilicon layer. The stacked capacitor is formed at the surface of a semiconductor substrate of a first conductivity type. The stacked capacitor has a bottom plate that is formed by a lightly doped well diffused into the surface of the semiconductor substrate. The bottom plate also has a first plurality of interconnected conductive layers of a first conductive material disposed above and aligned with the well, whereby a first conductive layer of the first plurality of conductive layers is connected to the well by multiple contacts distributed over an area of the well.