摘要:
A preferred embodiment of this invention comprises a conductive lightly donor doped perovskite layer (e.g. lightly La doped BST 34), and a high-dielectric-constant material layer (e.g. undoped BST 36) overlaying the conductive lightly donor doped perovskite layer. The conductive lightly donor doped perovskite layer provides a substantially chemically and structurally stable electrical connection to the high-dielectric-constant material layer. A lightly donor doped perovskite generally has much less resistance than undoped, acceptor doped, or heavily donor doped HDC materials. The amount of donor doping to make the material conductive (or resistive) is normally dependent on the process conditions (e.g. temperature, atmosphere, grain size, film thickness and composition). This resistivity may be further decreased if the perovskite is exposed to reducing conditions. The lightly donor doped perovskite can be deposited and etched by effectively the same techniques that are developed for the high-dielectric-constant material. The same equipment may used to deposit and etch both the perovskite electrode and the dielectric. These structures may also be used for multilayer capacitors and other thin-film ferroelectric devices such as pyroelectric materials, non-volatile memories, thin-film piezoelectric and thin-film electro-optic oxides.
摘要:
A structure for, and method of forming, a metal-insulator-semiconductor field-effect transistor in an integrated circuit is disclosed. The disclosed method comprises forming a germanium layer 52 on a semiconductor substrate (e.g. silicon 20), depositing a large-permittivity gate dielectric (e.g. tantalum pentoxide 56) on the germanium layer, and forming a gate electrode (e.g., titanium nitride 60) on the gate dielectric. The method may comprise forming source and drain regions 64 in the substrate on either side of the gate dielectric. The germanium layer, which is preferably epitaxially grown, generally prevents formation of a low dielectric constant layer between the gate dielectric and the semiconductor substrate. The disclosed structure comprises a germanium layer 52 disposed on a semiconductor substrate (e.g. silicon 20), a large-permittivity gate dielectric (e.g. tantalum pentoxide 56) disposed on the germanium layer, and a gate electrode (e.g., titanium nitride 60) disposed on the gate dielectric. The structure may comprise source and drain regions 64 disposed in the substrate on either side of the gate dielectric. A GexSi1-x buffer layer 58 may be formed between the semiconductor substrate and the germanium layer, with x transitioning from about 0 near the substrate to about 1 near the germanium layer. The large-permittivity gate dielectric may be either a moderate-dielectric constant oxide or a high-dielectric constant oxide.
摘要:
A ferroelectric structure on an integrated circuit is disclosed, which may be used, for instance, in a high-speed, non-volatile, non-destructive readout random-access memory device. Generally, the ferroelectric structure combines a thin film ferroelectric variable resistor and a substrate (e.g. silicon) transistor, using a semiconducting film which is common to both. A field effect transistor 26 integrated into substrate 30 has a gate oxide 36 and a semiconducting gate electrode 38 with electrical connections at a first end 44 and a second end 46. Overlying gate electrode 38 is a ferroelectric thin film 40 and a conductive electrode 42. The polarization of ferroelectric thin film 40 is set by applying an appropriate voltage between gate electrode 38 and conductive electrode 42. The polarization of ferroelectric thin film 40 may be subsequently determined by applying a read voltage to 42 and 44, thus causing a voltage V2 to appear at 46 which is determined by the polarization of the ferroelectric variable resistor formed by 38 and 40. Since 38 also forms the gate electrode for field effect transistor 26, the magnitude of V2 affects the magnitude of current I2. Thus I2 is effectively an amplified signal related to the ferroelectric variable resistance which may be read without perturbing the polarization of ferroelectric thin film 40.
摘要:
A method and structure for etching a thin film perovskite layer (e.g., barium strontium titanate 836) overlying a second material without substantially etching the second material. The method comprises forming a substantially-silicon-free dielectric etchstop layer (e.g., aluminum nitride 858) on a second dielectric layer comprising silicon (e.g., silicon dioxide 818), depositing the perovskite layer over the etchstop layer, forming a mask layer (e.g., photoresist 842) over the perovsklte layer, patterning and removing portions of the mask layer to form a desired pattern, and etching portions of the perovskite layer not covered by the mask layer, whereby the etching stops on the etchstop layer. The structure comprises a substantially-silicon-free dielectric etchstop layer overlying a second dielectric layer comprising silicon, and a perovskite layer having a desired pattern and comprising an etched side overlying a substantially unetched portion of the etchstop layer.
摘要:
A method for etching a feature in a platinum layer 834 overlying a second material 818 without substantially etching the second material. The method includes the the steps of: forming an adhesion-promoting layer 824 between the platinum layer and the second material; forming a hardmask layer 829 over the platinum layer; patterning and etching the hardmask layer in accordance with desired dimensions of the feature; and etching portions of the platinum layer not covered by the hardmask layer 832, the etching stopping on the adhesion-promoting layer. In further embodiments the adhesion-promoting and hardmask layers are Ti--Al--N including at least 1% of aluminum.
摘要:
This is a method for fabricating a structure useful in semiconductor circuitry. The method comprises: growing a buffer layer of non-Pb/Bi-containing high-dielectric constant oxide layer directly or indirectly on a semiconductor substrate; and depositing a Pb/Bi-containing high-dielectric constant oxide on the buffer layer. Alternately this may be a structure useful in semiconductor circuitry, comprising: a buffer layer 26 of non-lead-containing high-dielectric constant oxide layer directly or indirectly on a semiconductor substrate 10; and a lead-containing high-dielectric constant oxide 28 on the buffer layer. Preferably a germanium layer 12 is epitaxially grown on the semiconductor substrate and the buffer layer is grown on the germanium layer. When the substrate is silicon, the non-Pb/Bi-containing high-dielectric constant oxide layer is preferably less than about 10 nm thick. A second non-Pb/Bi-containing high-dielectric constant oxide layer 30 may be grown on top of the Pb/Bi-containing high-dielectric constant oxide and a conducting layer (top electrode 32) may also be grown on the second non-Pb/Bi-containing high-dielectric constant oxide layer.
摘要:
A preferred embodiment of this invention comprises a first thin dielectric buffer layer of a first leakage-current-density material (e.g. strontium titanate 32) with a first moderate-dielectric-constant, a high-dielectric-constant layer of a second leakage-current-density material (e.g. barium strontium titanate 34) overlaying the first thin dielectric buffer layer, and a second thin dielectric buffer layer of a third leakage-current-density material (e.g. strontium titanate 36) with a second moderate-dielectric-constant overlaying the high-dielectric-constant layer, wherein the first and third leakage-current-density materials have substantially lower leakage-current-densities than the second leakage-current-density material. The first and second thin moderate-dielectric-constant buffer layers (e.g. strontium titanate 32, 36) substantially limit the leakage-current-density of the structure, with only modest degradation of the dielectric constant of the structure. The possibly lower dielectric constant of the structure is generally compensated for by the reduced leakage current of the structure. The additional layers generally require only minor modifications of existing processes, since the same processes that are used for the high-dielectric-constant oxide can generally be used for the low leakage-current-density dielectric. These structures may also be used for multilayer capacitors and other thin-film ferroelectric devices such as pyroelectric materials, non-volatile memories, thin-film piezoelectric and thin-film electro-optic oxides.
摘要:
A preferred embodiment of this invention comprises an oxidizable layer (e.g. TiN 50), an noble-metal-insulator-alloy barrier layer (e.g. Pd-Si-N 34) overlying the oxidizable layer, an oxygen stable layer (e.g. platinum 36) overlying the noble-metal-insulator-alloy layer, and a high-dielectric-constant material layer (e.g. barium strontium titanate 38) overlying the oxygen stable layer. The noble-metal-insulator-alloy barrier layer substantially inhibits diffusion of oxygen to the oxidizable layer, thus minimizing deleterious oxidation of the oxidizable layer.
摘要:
A preferred embodiment of this invention comprises an oxidizable layer (e.g. TiN 50), an noble-metal-insulator-alloy barrier layer (e.g. Pd-Si-N 34) overlying the oxidizable layer, an oxygen stable layer (e.g. platinum 36) overlying the noble-metal-insulator-alloy layer, and a high-dielectric-constant material layer (e.g. barium strontium titanate 38) overlying the oxygen stable layer. The noble-metal-insulator-alloy barrier layer substantially inhibits diffusion of oxygen to the oxidizable layer, thus minimizing deleterious oxidation of the oxidizable layer.
摘要:
An array of thermal sensor elements (16) is formed from a pyroelectric substrate (46) having an infrared absorber and common electrode assembly (18) attached thereto. A first layer of metal contacts (60) is formed to define masked (61) and unmasked (68) regions of the substrate (46). A second layer of metal contacts (62) is formed on the first layer of contacts (60). A radiation etch mask layer (66) is formed to encapsulate the exposed portions of the second layer of contacts (62). A dry-etch mask layer (74) is formed to encapsulate the exposed portions of the first layer of contacts (60) and radiation etch mask layer (66). An initial portion of each unmasked region (68) is etched using a dry-etch process. The remaining portions of the unmasked regions (68) are exposed to an etchant (70) and irradiated with electromagnetic energy to substantially increase the reactivity between the remaining portions and the etchant (70). During such irradiation, the etchant (70) etches the remaining portions substantially faster than the first layer of contacts (60) and the radiation etch mask layer (66).