Abstract: The present invention relates to various methods of fabricating Planar Bragg Gratings (PBG) in a doped waveguide in a Planar Lightwave Circuit (PLC) device, suppressing unwanted parasitic grating effects during fabrication of the device. One approach to reduce parasitic gratings is to use a hard mask before the waveguide photolithography and etch, that results in a steeper sidewall angle that reduces or eliminates the parasitic grating effect. Another method of reducing parasitic grating effect is to deposit a layer of developable Bottom Anti Reflective Coating (BARC) prior to depositing the photo resist for waveguide etch. A third method of resisting parasitic gratings comprises using a planarizing undoped silica layer as a barrier layer on top of the core. During subsequent high temperature annealing germanium outdiffuses laterally into the cladding.

Abstract: The present invention relates to various methods of fabricating Planar Bragg Gratings (PBG) in a doped waveguide in a Planar Lightwave Circuit (PLC) device, suppressing unwanted parasitic grating effects during fabrication of the device. One approach to reduce parasitic gratings is to use a hard mask before the waveguide photolithography and etch, that results in a steeper sidewall angle that reduces or eliminates the parasitic grating effect. Another method of reducing parasitic grating effect is to deposit a layer of developable Bottom Anti Reflective Coating (BARC) prior to depositing the photo resist for waveguide etch. A third method of resisting parasitic gratings comprises using a planarizing undoped silica layer as a barrier layer on top of the core. During subsequent high temperature annealing germanium outdiffuses laterally into the cladding.

Abstract: A nitride layer is deposited over a field oxide layer used to separate transistors formed in a substrate, the nitride layer serving to decrease transistor current leakage. The nitride layer has a dense lattice, effectively blocking H+ and Na+ penetration from overlying layers into the field oxide. Positive ions such as H+ and Na+ penetrating into the field oxide layer cause a p-substrate under the field oxide layer to become inverted or act like an n-type substrate, creating leakage current between source and drain regions of transistors which the field oxide layer separates. When high transistor threshold voltages such as 12 volts or more are desired, the nitride layer provides a significant reduction in current leakage.

Abstract: A nitride layer is deposited over a field oxide layer used to separate transistors formed in a substrate, the nitride layer serving to decrease transistor current leakage. The nitride layer has a dense lattice, effectively blocking H+ and Na+ penetration from overlying layers into the field oxide. Positive ions such as H+ and Na+ penetrating into the field oxide layer cause a p-substrate under the field oxide layer to become inverted or act like an n-type substrate, creating leakage current between source and drain regions of transistors which the field oxide layer separates. When high transistor threshold voltages such as 12 volts or more are desired, the nitride layer provides a significant reduction in current leakage.

Abstract: This invention includes a semiconductor device having a gate formed on a semiconductor substrate with a low hydrogen content etch stop or barrier layer formed over the gate, and methods for manufacturing a semiconductor device with an etch stop or barrier layer with low free hydrogen content. The semiconductor device may have a hydrogen getter layer formed between the gate and the etch stop or barrier layer. The etch stop or barrier layer is a high temperature PECVD nitride film, a high temperature PECVD oxynitride film or a high temperature LPCVD nitride film. The hydrogen getter layer is P-doped film having a thickness between about 500 .ANG. and about 2000 .ANG. and is a PSG, BPSG, PTEOS deposited oxide film, or a BPTEOS deposited oxide film. The low free hydrogen content of the etch stop layer or barrier layer is achieved by a high temperature annealing step, performed at a higher temperature than the deposition temperature of the etch stop or barrier layer.

Abstract: A shallow trench isolation structure and a method for forming the same for use with non-volatile memory devices is provided so as to maintain sufficient data retention thereof. An epitaxial layer is formed on a top surface of a semiconductor substrate. A barrier oxide layer is formed on a top surface of the epitaxial layer. A nitride layer is deposited on a top surface of the barrier oxide layer. Trenches are formed through the epitaxial layer and the barrier oxide layer to a depth greater than 4000 .ANG. below the surface of the epitaxial layer so as to create isolation regions in order to electrically isolate active regions in the epitaxial layer. A liner oxide is formed on sidewalls and bottom of the trenches to a thickness between 750 .ANG. to 1500 .ANG.. As a result, leakage current in the sidewalls are prevented due to less thinning of the liner oxide layer by subsequent fabrication process steps.

Abstract: Controlling the thickness of borophosphorous tetraethyl orthosilicate (BPTEOS) used as all or part of the first inter-layer dielectric (ILD0) in manufacturing a semiconductor device containing an array of transistors to control the field leakage between transistors. Reducing field leakage enables the thickness of field oxide, typically used to reduce field leakage, to be reduced to increase device density in the transistor array.

Abstract: A shallow trench isolation structure and a method for forming the same for use with non-volatile memory devices is provided so as to maintain sufficient data retention thereof. An epitaxial layer is formed on a top surface of a semiconductor substrate. A barrier oxide layer is formed on a top surface of the epitaxial layer. A nitride layer is deposited on a top surface of the barrier oxide layer. Trenches are formed through the epitaxial layer and the barrier oxide layer to a depth greater than 4000 .ANG. below the surface of the epitaxial layer so as to create isolation regions in order to electrically isolate active regions in the epitaxial layer. A liner oxide is formed on sidewalls and bottom of the trenches to a thickness between 750 .ANG. to 1500 .ANG.. As a result, leakage current in the sidewalls are prevented due to less thinning of the liner oxide layer by subsequent fabrication process steps.

Abstract: A method for improving the endurance and reliability of a floating gate transistor often used in memory applications by controlling the electric field induced across the tunnel oxide region of the floating gate when discharging electrons from the floating gate. The method comprises the steps of: allowing the active region to ground; and applying a program voltage to the floating gate over a period of time and at a magnitude, by increasing the voltage from zero volts to the magnitude over a first period of at least 1 millisecond (ms.), maintaining the voltage at the magnitude for a second period of around 10 ms.-100 ms. sufficient to place charge on the floating gate, and decreasing the voltage from the magnitude during a third period to zero volts in not greater than 50 microseconds.

Abstract: A process for forming CMOS transistors on a semiconductor substrate, wherein the plurality of transistors includes high-voltage N-channel and high-voltage P-channel transistors, and low-voltage N-channel and low-voltage P-channel transistors, wherein a tunnel oxide of a first thickness is required and a gate oxide of a second thickness is required is provided.

Abstract: An enhanced, scalable EEPROM memory cell is provided with a structure having a plurality of half-height tunnel oxide depletion mode transistors. The structure further has individual wordlines controlling the write and read transistors, respectively. With such a structure, lower voltages are used to program/erase the memory cell. The memory cell is scalable to small dimensions through the use of transistors having half-height tunnel oxide regions.

Abstract: An improved method for screening a non-volatile memory device or programmable logic device including the steps of initially programming and then erasing a device for a predetermined number of cycles thereby providing a stressed device. Next, the stressed device is erased, providing an erased device. A first voltage value is measured across the floating gate of each cell of the erased device which is then stored for a predetermined period of time at a first predetermined temperature, providing a stored device. Next, the stored device is baked at a second predetermined temperature resulting in a baked device. Then, a second voltage value is measured across the floating gate of each cell of the baked device. Each of the first and the second voltage values are subtracted to provide a plurality of measured voltage drop values each of which are compared to an acceptable predetermined voltage drop value.

Abstract: An apparatus and method, the apparatus including an NMOS pass gate separating NMOS and PMOS transistors of a CMOS memory cell configured for tunneling during program and erase through the NMOS and PMOS transistors. The additional NMOS pass gate enables the CMOS memory cell to be utilized as a memory cell in a programmable logic device (PLD). The method includes steps for programming and erasing CMOS memory cells to prevent current leakage. The steps include applying specific voltages to the sources of the NMOS and PMOS transistors during program and erase, rather than leaving either source floating. Such voltages can be applied during program or erase without additional pass gates being connected to the sources of the PMOS or NMOS transistors of individual CMOS cells, or the additional pass gate provided between the drains of the PMOS and NMOS as in the described apparatus.

Abstract: An improved control gate-addressed CMOS memory cell is provided which allows for programming and erasing by tunneling through the gate oxides of the PMOS and NMOS transistors. The CMOS memory cell (400) includes a PMOS transistor (402), an NMOS transistor (403), and an NMOS pass transistor (405). A capacitor (430) has a first terminal coupled to a common floating gate (416) of the PMOS and NMOS transistors and has a second terminal coupled to a control gate node.

Abstract: Circuitry added to CMOS memory cell configured to enable tunneling through its PMOS and NMOS transistors, the circuitry preventing leakage current during programming. The circuitry includes a separate NMOS pass gate for connecting the source of the NMOS transistor of the CMOS cell to Vss. The gate of the NMOS pass gate is controlled to turn off the NMOS transistor during programming through the PMOS transistor to prevent current loss on the Vss line. The NMOS pass gate further provides a means for enabling or disabling the NMOS transistor making the CMOS cell useful as an array cell for a PAL device.

Abstract: A CMOS memory cell including PMOS and NMOS transistors with a common floating gate. The CMOS memory cell includes a first capacitor connecting a first control voltage to the common floating gate and a second tunneling capacitor connected from the common floating gate to the source of the NMOS transistor. The tunneling capacitor includes a tunneling oxide region utilized to charge or discharge the floating gate during program or erase. The CMOS cell further includes a pass transistor with a source to drain path connecting the source of the NMOS transistor to a second control voltage.