1. A phototransistor having a substrate and a layer formed on the substrate containing laterally spaced emitter and collector regions of a first conductivity type and a base region of a second opposite conductivity type located between the emitter and collector regions, a depletion region being formed between the base region and the emitter region and including the whole of the base region.
2. A phototransistor according to claim 1 in which said depletion region includes the whole of the base region only upon a bias voltage being applied between the base and emitter regions.
3. A phototransistor having a substrate and a layer formed on the substrate containing laterally spaced emitter and collector regions of a first conductivity type and a base region of a second opposite conductivity type located between the emitter and collector regions, the base region having a width no more than about 4 m and having a charge carrier concentration of no more than about 1016 cm3.
4. A phototransistor according to claim 1, claim 2 or claim 3 in which the emitter, collector and base regions are doped regions of an element semiconductor.
5. A phototransistor according to claim 3 in which the element semiconductor is silicon.
6. A phototransistor according to any preceding claim having an insulating layer between the substrate and the emitter, collector and base regions.
7. A phototransistor according to any preceding claim in which an oxide layer is formed covering at least part of the base region.
8. A phototransistor according to any preceding claim in which the first conductivity type is n-type and the second conductivity type is p-type.
9. A phototransistor according to any preceding claim in combination with circuitry arranged to generate a bias voltage between the base and emitter regions adequate to generate a depletion region which includes the whole of the base region.
10. A method of operating a phototransistor according to any preceding claim, the method comprising using applying a bias voltage between the emitter and collector regions to generate the depletion region including the whole of the base region, exposing the phototransistor to illumination, and measuring the current conducted from the emitter region to the collector region.
11. A method according to claim 10 in which the bias voltage is in the range 2 to 6 volts.
The claims below are in addition to those above.
All refrences to claim(s) which appear below refer to the numbering after this setence.
1. A three-dimensional microstructure formed by a sequential build process, comprising:
a first microstructural element formed of a first material;
a second microstructural element formed of a second material;
a substrate over which the first microstructural element and the second microstructural element are disposed; and
a non-solid volume to which the first microstructural element andor the second microstructural element are exposed,
wherein, the first microstructural element comprises a patterned locking portion disposed at least partially through the second microstructural element to mechanically lock the first microstructural element and the second microstructural element.
2. The three-dimensional microstructure of claim 1, wherein the patterned locking portion is rounded.
3. The three-dimensional microstructure of claim 1, wherein the microstructure comprises a coaxial transmission line comprising a center conductor, an outer conductor and a dielectric support member for supporting the center conductor, wherein the dielectric support member is the first microstructural element, and the inner conductor andor the outer conductor is the second microstructural element.
4. The three-dimensional microstructure of claim 3, wherein the non-solid volume is under vacuum or in a gas state, and is disposed between the center conductor and the outer conductor.
5. The three-dimensional microstructure of claim 3, wherein the coaxial transmission line has a generally rectangular coaxial geometry.
6. The three-dimensional microstructure of claim 3, wherein the dielectric support member comprises at least one patterned locking portion at opposing ends of the dielectric support member in mechanically locking engagement with opposing surfaces of the outer conductor.
7. The three-dimensional microstructure of claim 1, wherein the patterned locking portion comprises an aperture extending at least partially through the first microstructural element.
8. The three-dimensional microstructure of claim 7, wherein metal material is disposed in the aperture affixing the first microstructural element to the second microstructural element.
9. The three-dimensional microstructure of claim 8, wherein the second microstructural element comprises metal material and the metal material in the aperture is of the same metal material as the metal material of the second microstructural element.
10. The three-dimensional microstructure of claim 7, wherein the aperture has a reentrant shape.
11. The three-dimensional microstructure of claim 7, wherein the aperture extends completely through the first microstructural element from a first surface to a second surface thereof.
12. The three-dimensional microstructure of claim 1, wherein the patterned locking portion comprises a reentrant profile.
13. A method of forming a three-dimensional microstructure by a sequential build process, comprising:
forming a plurality of layers over a substrate, wherein the layers comprise at least one of a first material, a second material and a sacrificial material;
forming a first microstructural element comprising the first material and including a patterned locking portion;
forming a second microstructural element comprising the second material; and
removing the sacrificial material to form a non-solid volume to which the first microstructural element andor the second microstructural element are exposed,
wherein, the patterned locking portion is disposed at least partially through the second microstructural element to mechanically lock the first microstructural element and the second microstructural element.
14. The method of claim 13, wherein the patterned locking portion comprises a reentrant profile.
15. The method of claim 13, wherein the patterned locking portion comprises an aperture extending at least partially therethrough.
16. The method of claim 15, comprising depositing a metal material in the aperture, affixing the first microstructural element to the second microstructural element.
17. The method of claim 13, wherein the first material is a dielectric material and the second material is a metal material.
18. The method of claim 13, wherein the microstructure comprises a coaxial transmission line comprising a center conductor, an outer conductor and a dielectric support member for supporting the center conductor, wherein the dielectric support member is the first microstructural element, and the inner conductor andor the outer conductor is the second microstructural element.
19. A three-dimensional microstructure formed by a sequential build process, comprising:
a first microstructural element formed of a first material;
a second microstructural element formed of a second material; and
a non-solid volume to which the first microstructural element andor the second microstructural element are exposed,
the first microstructural element comprising a patterned locking portion including a reentrant profile and disposed at least partially through the second microstructural element to mechanically lock the first microstructural element and the second microstructural element.
20. A three-dimensional microstructure formed by a sequential build process, comprising:
a first microstructural element formed of a first material;
a second microstructural element formed of a second material; and
a non-solid volume to which the first microstructural element andor the second microstructural element are exposed,
the first microstructural element comprising a patterned locking portion disposed at least partially through the second microstructural element to mechanically lock the first microstructural element and the second microstructural element,
the microstructure including a coaxial transmission line comprising a center conductor, an outer conductor and a dielectric support member for supporting the center conductor, the dielectric support member being the first microstructural element, and the inner conductor andor the outer conductor being the second microstructural element,
the dielectric support member comprising a patterned locking portion at opposing ends of the dielectric support member in mechanically locking engagement with opposing surfaces of the outer conductor.
21. A three-dimensional microstructure formed by a sequential build process, comprising:
a first microstructural element formed of a first material;
a second microstructural element formed of a second material; and
a non-solid volume to which the first microstructural element andor the second microstructural element are exposed,
the first microstructural element comprising a patterned locking portion disposed at least partially through the second microstructural element to mechanically lock the first microstructural element and the second microstructural element,
the patterned locking portion comprising an aperture extending at least partially through the first microstructural element and including a reentrant shape.
22. A three-dimensional microstructure formed by a sequential build process, comprising:
a first microstructural element formed of a first material;
a second microstructural element formed of a second material; and
a non-solid volume to which the first microstructural element andor the second microstructural element are exposed,
the first microstructural element comprising a patterned locking portion disposed at least partially through the second microstructural element to mechanically lock the first microstructural element and the second microstructural element,
the patterned locking portion comprising an aperture extending at least partially through the first microstructural element,
wherein metal material is disposed in the aperture affixing the first microstructural element to the second microstructural element.
23. A three-dimensional microstructure formed by a sequential build process, comprising:
a first microstructural element formed of a first material;
a second microstructural element formed of a second material; and
a non-solid volume to which the first microstructural element andor the second microstructural element are exposed,
the first microstructural element comprising a patterned locking portion disposed at least partially through the second microstructural element to mechanically lock the first microstructural element and the second microstructural element,
the patterned locking portion comprising an aperture extending completely through the first microstructural element from a first surface to a second surface thereof.