Semiconductor device with multilayer silicon oxide silicon nitride dielectric

A capacitor integrally constructed with a semiconductor device, the capacitor comprising:

• a substrate;
• a lower electrode including a layer of polycrystalline silicon having a first surface abutting and supported on the substrate and a thin natural oxide film of less than 2 nm formed on a second surface thereof which second surface is parallel to the first surface and faces from the supporting substrate;
• a multilayer dielectric including a layer of silicon-nitride disposed on the natural oxide film and a layer of silicon oxide, the silicon-nitride layer being between 3 nm and 18 nm thick and the silicon oxide layer being between 1 nm and 81/2 nm thick;
• and,
• an upper electrode mounted to the multilayer dielectric.

A solid state device comprising:

• a doped substrate;
• first and second doped regions supported by the substrate;
• a gate insulated from and supported by the substrate between the first and second regions;
• thick insulation film covering the gate and a portion of substrate adjacent the first region;
• a polycrystalline silicon layer having a first surface supported by the first region and the thick insulation film and a second surface facing away from the substrate;
• a natural oxide film on the second surface of the polycrystalline layer;
• a first dielectric layer including a silicon-nitrogen composition deposited on the natural oxide film;
• a second dielectric layer including a silicon-oxygen composition on the first dielectric layer;
• the first dielectric layer having a thickness that is greater than:
• ##EQU7## and less than ##EQU8## where t.sub.2 is a thickness of the second dielectric layer, t.sub.o is a thickness of the natural oxide film E.sub.SiN is a dielectric constant of the silicon-nitrogen composition, and E.sub.SiO is a dielectric constant of the silicon-oxygen composition.

A capacitor integrally constructed with an MOS transistor comprising:

• a doped substrate in which two regions doped with an n-type impurity are defined;
• a gate surrounded by an insulator and supported by the substrate between the two regions;
• a first polycrystalline silicon electrode with a natural oxide less than 1 nm thick on one surface thereof, the polycrystalline electrode having another surface in electrical communication with one of the regions and extending at least partially along the gate insulation, the first polycrystalline silicon electrode being supported by the one region and the gate electrode insulation;
• a multilayer dielectric including a layer of silicon-nitride disposed on the natural oxide and a layer of silicon oxide, the silicon-nitride layer being between 3 nm and 18 nm thick and the silicon oxide layer being between 1 nm and 81/2 nm thick;
• and,
• a second electrode mounted to the multilayer dielectric.

A solid state device comprising:

• a substrate;
• a polycrystalline silicon layer having a first surface supported by the substrate and a second surface facing away from the substrate;
• a natural oxide film less than 2 nm thick on the second surface of the polycrystalline silicon layer;
• a silicon-nitrogen composition layer disposed on the oxide film and supported by the polycrystalline silicon layer;
• a silicon-oxygen composition layer disposed on and supported by the first dielectric layer;
• the first dielectric layer having a thickness that is greater than:
• ##EQU9## and less than ##EQU10## where t.sub.2 is a thickness of the second dielectric layer, t.sub.o is a thickness of the natural oxide film, E.sub.SiN is a dielectric constant of the silicon-nitrogen composition, and E.sub.SiO is a dielectric constant of the silicon-oxygen composition.