Abstract: A process for fabricating multi-level semiconductor ROM devices is disclosed. Each memory cell of the ROM device can be programmed to any of three possible conduction states including full-conduction, half-conduction and no-conduction. The fabrication process begins with a semiconductor silicon substrate. Buried bit and word lines are formed in the substrate. A photomask is then formed to correspond to code to be programmed into the ROM device. The photomask, when properly aligned over the ROM device, contains portions that fully cover the entire channel region of a cell to be programmed for full conduction, portions that partially cover the channel regions of cells that are to be programmed for half-conduction, and portions that do not cover at all the channel regions of cells to be programmed for no-conduction. Then ions are implanted with the photomask in place. The ions transform the regions not covered or partially covered by the photomask.

Abstract: A method of measuring the leakage current of a DRAM capacitive junction involves the of following steps: A DRAM memory is formed on a semiconductor substrate. The DRAM memory comprises a plurality of RAM memory cells and a measuring memory cell. Each of the RAM memory cells and the measuring memory cell includes a transistor and a capacitor serially connected. The contact area of a bottom plate of the capacitor of the measuring memory cell is much larger than that of the RAM memory cells. A first junction leakage current value is measured while the transistor of the measuring memory cell is turned off. A second junction leakage current value is measured while the transistor of the measuring memory cell is turned on. The first junction leakage current value then is subtracted from the second junction leakage current value.

Abstract: A process of fabricating an array of floating gate memory devices on a substrate comprises forming elongated spaced apart parallel ion implanted field implant regions in the substrate, forming elongated spaced apart parallel buried bit lines in the substrate orthogonally directed relative to the field implant regions, forming field oxide regions over the buried bit lines and field implant regions, and growing a silicon dioxide gate oxide layer having a thickness of from approximately 80 .ANG. to approximately 300 .ANG. between the field oxide regions, forming a plurality of first gate members from a first layer of polysilicon, the first gate members being disposed over the gate oxide layer, forming a layer of interpolysilicon dielectric over the first gate members having a thickness of approximately 150 .ANG.

Abstract: A voltage detector for determining the high or low status of a power supply output voltage, including a front-end detector and an inverting amplifier. The front-end detector includes a number of NMOS and PMOS transistors which constitute active loads. The voltage detector is inherently independent of device fabrication condition changes, as well as on the temperature variations.

Abstract: A process of fabricating an array of floating gate memory devices on a substrate comprises forming elongated spaced apart parallel ion implanted field implant regions in the substrate, forming elongated spaced apart parallel buried bit lines in the substrate orthogonally directed relative to the field implant regions, forming field oxide regions over the buried bit lines and field implant regions, and growing a silicon dioxide gate oxide layer having a thickness of from approximately 80 .ANG. to approximately 300 .ANG. between the field oxide regions, forming a plurality of first gate members from a first layer of polysilicon, the first gate members being disposed over the gate oxide layer, forming a layer of interpolysilicon dielectric over the first gate members having a thickness of approximately 150 .ANG.

Abstract: A process of fabricating a semiconductor device on a substrate with closely spaced high density conductive lines is provided. A thin insulating layer is formed on the surface of a substrate. Next, a blanket conductive layer and a blanket masking layer are deposited over the first insulating layer. Using conventional photolithography processes and plasma etching, elongated spaced parallel masking lines with vertical sidewalls are formed in the masking layer. A blanket polycrystalline silicon layer is deposited on the masking lines and the exposed areas of the conductive layer. Next, the blanket polycrystalline silicon layer is anisotrophically etched to form spacers on the vertical sidewalls of the masking lines. A second planarized masking layer is formed over the spacers and masking lines. The polycrystalline silicon spacers and the underlying first polycrystalline silicon layer are anisotrophically etched to form the closely spaced conductive lines in the first polycrystalline silicon layer.

Abstract: A process of fabricating a non-volatile read only memory device (ROM) wherein the conductive word lines have desirable very narrow widths and are closely spaced. The invention provides a process for forming word lines with a smaller width and line pitch than is possible with conventional processes. A first set of word lines is formed. Next, a second set of word lines is formed in between the first word lines using oxide spacers to define the second word lines.

Abstract: An FET thin film transistor is formed with a channel formed of a Si/Si.sub.1-x Ge.sub.x /Si three layer sandwich which serves as the carrier transfer channel. The percentage of germanium is preferably less than 30% and should be less than about 50%. The TFT can be structured as top gate, bottom gate or twin gate structure. The Si/Si.sub.1-x Ge/Si sandwich layer is processed in a continuous process under computer control.

Abstract: A new method of forming a self-aligning polysilicon gate is described. A gate silicon oxide is formed over a silicon substrate. A polysilicon layer is formed over the gate oxide. A native silicon oxide layer is formed over the polysilicon layer. A second polysilicon layer is formed over the native silicon oxide layer. Additional alternating layers of polysilicon and native silicon oxide are formed as desired. The wafer is annealed at between about 800.degree. to 1000.degree. C. This causes, it is believed, the silicon oxide gas from the multiple native silicon oxide layers to be exhausted resulting in the removal of all silicon oxide layers. A polycide layer is formed overlying the multiple polysilicon layers, if desired. Conventional lithography and etching techniques are used to form a gate. Ions are implanted into the substrate to form source/drain regions, using the multilayer gate as a mask. Rapid thermal annealing activates the impurities.

Abstract: A new method of forming polysilicon buried contact to source/drain or emitter regions is described. A silicon oxide layer is formed over the silicon substrate. An opening is formed to the silicon substrate at the location of the desired buried contact to source/drain or emitter region via conventional techniques. A hydrofluoric acid solution is used to remove the native silicon oxide which forms on the exposed surface of the silicon substrate. Some native silicon oxide is formed in a controlled manner again on the surface of the silicon substrate. The wafer is put into a low pressure chemical vapor deposition (LPCVD) apparatus and a layer of undoped polysilicon or amorphous silicon is deposited. An oxidizer is added to the deposition chamber or the wafer is exposed to ambient air so that a thin layer of native silicon oxide is formed in a controlled manner overlying the polysilicon layer. Additional alternating layers of polysilicon and native silicon oxide are formed as desired.