Abstract:
A detector device (75) for detecting incident radiation at particular wavelengths is disclosed. The device (75) includes a base layer comprising a substrate (77). A resonant cavity is formed on the base layer between a pair of reflectors. One reflector is formed by a first reflector layer (83) disposed in fixed relationship with respect to the base layer and the other reflector is formed by a second reflector layer (91) disposed on a membrane (89) in substantially parallel relationship to the substrate (77). A detector (79) is provided within the cavity to absorb incident radiation therein for detection purposes. By placing the absorbing layer of the detector (79) within the resonant cavity, high quantum efficiency can be achieved using very thin absorbing layers, thus significantly reducing the detector volume and hence noise. Various different arrangements of the detector device (75) and different methods of fabricating the same are also disclosed.
Abstract:
A tunable cavity resonator for filtering radiation in the optical and IR wavelengths and a method for fabricating same. The resonator having a pair of reflectors, one in fixed relationship to a substrate and the other formed upon a suspended moveable membrane disposed a cavity length from the one reflector. The resonator also including a pair of spaced apart electrodes either constituted by the reflectors or juxtaposed therewith, which are electrostatically operable to move the membrane and other reflector relative to the one reflector. A first reflector layer is deposited on the substrate to form the one reflector. A sacrificial layer having a high etch selectivity for releasing the membrane in a suspended and spaced relationship from the one reflector is formed on the first reflector layer. The membrane is deposited on the sacrificial layer using a deposition technique characterised by providing the required intrinsic stress in the membrane. A second reflector layer is formed on the membrane to form the other reflector. The second reflector layer is patterned in accordance with a prescribed membrane geometry and then etched to achieve the same. The sacrificial layer is then initially etched to remove regions thereof down to the first reflector layer on the substrate exposed by the etching. Those regions of the sacrificial layer that are intended to function as the residual support structure of the membrane are then protected with photoresist and the remaining unprotected regions of the sacrificial layer are finally etched, removing the protection from the support structures to suspend the membrane in substantially parallel relation to the first reflector layer.
Abstract:
An example tunable cavity resonator for filtering radiation in the optical and IR wavelengths and an example method for fabricating same. The example resonator includes a pair of reflectors, one in fixed relationship to a substrate and the other formed upon a suspended moveable membrane disposed a cavity length from the one reflector. The resonator also includes a pair of spaced apart electrodes either constituted by the reflectors or juxtaposed therewith, which are electrostatically operable to move the membrane and other reflector relative to the one reflector.
Abstract:
An example tunable cavity resonator for filtering radiation in the optical and IR wavelengths and an example method for fabricating same. The example resonator includes a pair of reflectors, one in fixed relationship to a substrate and the other formed upon a suspended moveable membrane disposed a cavity length from the one reflector. The resonator also includes a pair of spaced apart electrodes either constituted by the reflectors or juxtaposed therewith, which are electrostatically operable to move the membrane and other reflector relative to the one reflector.
Abstract:
A detector device for detecting incident radiation at particular wavelengths is disclosed. The device includes a base layer comprising a substrate. A resonant cavity is formed on the base layer between a pair of reflectors. One reflector is formed by a first reflector layer disposed in fixed relationship with respect to the base layer and the other reflector is formed by a second reflector layer disposed on a membrane in substantially parallel relationship to the substrate. A detector is provided within the cavity to absorb incident radiation therein for detection purposes. By placing the absorbing layer of the detector within the resonant cavity, high quantum efficiency can be achieved using very thin absorbing layers, thus significantly reducing the detector volume and hence noise. Various different arrangements of the detector device and different methods of fabricating the same are also disclosed.
Abstract:
An automatically passivated n-p junction is formed from a p-type body containing Group II and Group VI elements, one of which is mercury. A passivation layer is then formed having at least one window provided therein on a surface of the p-type body. The p-type body is then subjected to a reactive ion etching process using the passivation layer as a mask to form the n-p junction. Ohmic contacts are then formed on the n-type and p-type regions. The method may be extended to form an array of n-p junctions on a semiconductor body having a plurality of p-type material layers. This method comprises the further step of: etching the body to expose a portion of each layer; forming a passivation layer over the body; forming windows in the passivation layer; subjecting the body to a reactive ion etching process using the passivation layer as a mask to form an n-p junction in each layer or to form n-p junctions that extend substantially to the substrate; forming an ohmic contact to each of the n-type regions; and forming an ohmic contact to a common p-type layer or each layer of the portions. A semiconductor material comprising an n-p junction formed according to the aforementioned methods is also described, having a substrate, a layer of p-type material surmounting the substrate, a region of converted n-type material formed on a localised portion of the surface of the p-type material, so as to define an n-p junction between the p-type and the n-type material; a passivation layer surmounting the surface of the p-type material and the n-p junction, including windows respectively exposing part of the surface of the converted n-type material and a portion of the surface of the p-type material distant from the n-type material, such that ohmic contacts may be disposed on the exposed surface, without exposing the n-p junction.