1. A GaN-based field-effect transistor comprising:
a heterostructure including a channel layer and a barrier layer; and
an insulating film on a transistor device surface.
2. The field-effect transistor as claimed in claim 1, wherein the insulating film comprises any one of SiN, SiO2, SiON, Al2O3, and AlN.
3. The field-effect transistor as claimed in claim 1, wherein the insulating film comprises SiN formed by a hot wire CVD method.
4. The field-effect transistor as claimed in claim 1, wherein a change in an electron mobility in a range within 20 mm from a specific position of the field-effect transistor is equal to or less than 10%.
5. The field-effect transistor as claimed in claim 1, wherein a change in a two-dimensional electron density in a range within 20 mm from a specific position of the field-effect transistor is equal to or less than 10%.
6. The field-effect transistor as claimed in claim 1, wherein a thickness of the insulating film is 1 nm-1 \u03bcm.
7. The field-effect transistor as claimed in claim 1, wherein the insulating film comprises SiN formed by a hot wire CVD method, and a thickness of the insulating film is 1 nm-100 nm.
8. The field-effect transistor as claimed in claim 1, wherein the channel layer comprises GaN and the barrier layer comprises AlGaN.
9. The field-effect transistor as claimed in claim 1, wherein a thickness of the barrier layer is 1-30 nm.
10. The field-effect transistor as claimed in claim 1, wherein a thickness of the barrier layer is 3-20 nm.
11. The field-effect transistor as claimed in claim 1, wherein a thickness of the barrier layer is 5-15 nm.
12. The field-effect transistor as claimed in claim 1, wherein a thickness of the channel layer is 100 nm-10 \u03bcm.
13. A heterostructure field-effect transistor comprising:
a substrate having formed thereon a buffer layer, a channel layer of GaN, and a barrier of AlGaN having a thickness of 1-30 nm in this order; and
an insulating film on a transistor device surface.
14. The field-effect transistor as claimed in claim 13, wherein the insulating film comprises any one of SiN, SiO2, SiON, Al2O3, and AlN.
15. The field-effect transistor as claimed in claim 13, wherein the insulating film comprises SiN formed by a hot wire CVD method.
16. The field-effect transistor as claimed in claim 13, wherein a change in an electron mobility in a range within 20 mm from a specific position of the field-effect transistor is equal to or less than 10%.
17. The field-effect transistor as claimed in claim 13, wherein a change in a two-dimensional electron density in a range within 20 mm from a specific position of the field-effect transistor is equal to or less than 10%.
18. The field-effect transistor as claimed in claim 13, wherein a thickness of the insulating film is 1 nm-1 \u03bcm.
19. The field-effect transistor as claimed in claim 13, wherein the insulating film comprises SiN formed by a hot wire CVD method, and a thickness of the insulating film is 1 nm-100 nm.
20. The field-effect transistor as claimed in claim 13, wherein a spacer layer is provided between the channel layer and the barrier layer.
21. A method of producing a field-effect transistor having a heterostructure comprising:
a step of forming a buffer layer, a channel layer of GaN, and a barrier layer of AlGaN in this order on a substrate;
a step of forming a source electrode, a gate electrode, and a drain electrode; and
a step of forming an insulating film on a surface of the barrier layer.
22. The method of producing a field-effect transistor having a heterostructure as claimed in claim 21, wherein the step of forming the insulating film on the surface of the barrier layer uses any one of SiN,SiO2,SiON,Al2O3, and AlN as a raw material, and forms the insulating film by a hot wire CVD method.
23. The method of producing a field-effect transistor having a heterostructure as claimed in claim 21, wherein a thickness of the insulating film is 1 nm-1 \u03bcm.
24. The method of producing a field-effect transistor having a heterostructure as claimed in claim 21, wherein a thickness of the barrier layer of AlGaN is 3 nm-20 nm.
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 load control system for controlling the amount of power delivered from an AC power source to an electrical load provided in a space having a movable structure and a fixed surface, the load control system comprising:
a load control device adapted to be coupled in series electrical connection between the AC power source and the electrical load for control of the amount of power delivered to the electrical load, the load control device operable to receive wireless control signals and to control the amount of power delivered to the electrical load in response to the wireless control signals;
a first occupancy sensor adapted to be mounted to the movable structure, the first occupancy sensor operable to detect movement of the movable structure and to transmit a first occupied wireless control signal to the load control device in response to detecting the movement of the movable structure, the load control device operable to enable the delivery of power to the electrical load in response to receiving the first occupied wireless control signal; and
a second occupancy sensor adapted to be mounted to the fixed surface, the second occupancy sensor operable to detect an occupancy condition in the space and to transmit a second occupied wireless control signal to the load control device in response to detecting the occupancy condition;
wherein each of the occupancy sensors is operable to transmit a vacant wireless control signal to the load control device in response to detecting a vacancy condition in the space, the load control device operable to cease the delivery of power to the electrical load in response to receiving the vacant wireless control signals from both of the occupancy sensors;
wherein each of the occupancy sensors is operable to transmit a third wireless control signal to the load control device in response to detecting a continued occupancy condition in the space, the load control device ceasing the delivery of power to the electrical load in response to determining that no wireless control signals have been received from one of the occupancy sensors for the length of a predetermined timeout period, and receiving a vacant control signal from the other occupancy sensor;
wherein the load control device initializes a failsafe timer with the predetermined timeout period and restarts the failsafe timer in response to receiving the third wireless control signals from the occupancy sensors, the load control device operable to cease the delivery of power to the electrical load when the failsafe timer expires; and
wherein the first occupied wireless control signal comprises an occupied-take-action command, the second occupied wireless control signal comprises an occupied-take-action command and the third wireless control signal comprises an occupied-no-action command.
2. The load control system of claim 1, wherein the first and second occupancy sensors are each characterized by a unique serial number, the load control device comprising a memory for storage of the serial numbers of the two occupancy sensors, the load control device responsive to wireless control signals including at least one of the serial numbers of the first and second occupancy sensors.
3. The load control system of claim 1, wherein the load control device enables the delivery of power to the electrical load and starts the failsafe timer in response to receiving the occupied-take-action command.
4. The load control system of claim 2, wherein the load control device keeps track of the occupancy sensors from which the load control device received the occupied wireless control signals.
5. The load control system of claim 4, wherein the load control device ceases the delivery of power to the electrical load in response to receiving vacant control signals from all of the occupancy sensors from which the load control device received the occupied wireless control signals.
6. The load control system of claim 1, wherein the first occupancy sensor comprises an ambient light level detector for measuring the ambient light level in the space, the first occupancy sensor operable to compare the ambient light level to an ambient light level threshold and transmit an occupied-take-action command to the load control device in response to determining that the ambient light level is less than the threshold, and transmits an occupied-no-action command to the load control device in response to determining that the ambient light level is greater than the threshold.
7. The load control system of claim 6, wherein the first occupancy sensor measures the ambient light level only when the occupancy sensor first detects the movement of the movable structure.
8. The load control system of claim 6, wherein the load control device enables the delivery of power to the electrical load in response to receiving the occupied-take-action command.
9. The load control system of claim 6, wherein the load control device maintains constant the amount of power delivered to the electrical load in response to receiving the occupied-no-action command.
10. The load control system of claim 1, wherein the first occupancy sensor comprises a battery for powering the internal circuitry of the occupancy sensor.
11. The load control system of claim 1, wherein the first occupancy sensor comprises a PIR detector.
12. The load control system of claim 1, further comprising:
a remote control comprising an actuator and operable to transmit an actuator wireless control signal to the load control device in response to an actuation of the actuator, the load control device operable to control the amount of power delivered to the electrical load in response to the actuator wireless control signal.
13. The load control system of claim 1, wherein the electrical load is a lighting load and the load control device is a dimmer switch.
14. The load control system of claim 1, wherein the movable structure comprises a door, the first occupancy sensor mounted to an inside surface of the door to detect the movement of the door.
15. A load control system for controlling the amount of power delivered from an AC power source to an electrical load provided in a space having a door and a fixed surface, the load control system comprising:
a load control device adapted to be coupled in series electrical connection between the AC power source and the electrical load for control of the amount of power delivered to the electrical load, the load control device operable to receive wireless control signals and to control the amount of power delivered to the electrical load in response to the wireless control signals;
a first occupancy sensor adapted to be mounted to the door, the first occupancy sensor operable to detect movement of the door and to transmit a first occupied wireless control signal to the load control device in response to detecting the movement of the door, the load control device operable to enable the delivery of power to the electrical load in response to receiving the occupied wireless control signal from the first occupancy sensor; and
a second occupancy sensor adapted to be mounted to the fixed surface, the second occupancy sensor operable to detect an occupancy condition in the space and to transmit a second occupied wireless control signal to the load control device in response to detecting the occupancy condition;
wherein each of the occupancy sensors is operable to transmit a vacant wireless control signal to the load control device in response to detecting a vacancy condition in the space, the load control device operable to cease the delivery of power to the electrical load in response to receiving vacant control signals from both of the occupancy sensors;
wherein each of the occupancy sensors is operable to transmit a third wireless control signal to the load control device in response to detecting a continued occupancy condition in the space, the load control device ceasing the delivery of power to the electrical load in response to determining that no wireless control signals have been received from one of the occupancy sensors for the length of a predetermined timeout period, and receiving a vacant control signal from the other occupancy sensor;
wherein the load control device initializes a failsafe timer with the predetermined timeout period and restarts the failsafe timer in response to receiving the third wireless control signals, the load control device operable to cease the delivery of power to the electrical load when the failsafe timer expires; and
wherein the first occupied wireless control signal comprises an occupied-take-action command, and the third wireless control signal comprises an occupied-no-action command.
16. A method of controlling the amount of power delivered from an AC power source to an electrical load provided in a space having a movable structure and a fixed surface, the method comprising the steps of:
mounting a first occupancy sensor on the movable structure;
mounting a second occupancy sensor on the fixed surface;
the first occupancy sensor detecting movement of the movable structure;
the first occupancy sensor transmitting a first occupied wireless control signal in response to detecting the movement of the movable structure;
enabling the delivery of power to the electrical load in response to receiving the first occupied wireless control signal from the first occupancy sensor;
the second occupancy sensor detecting an occupancy condition in the space;
the second occupancy sensor transmitting a second occupied wireless control signal in response to detecting the occupancy condition in the space;
the first and second occupancy sensors each detecting a vacancy condition in the space;
the first and second occupancy sensors each transmitting a vacant wireless control signal in response to detecting the vacancy condition in the space; and
ceasing the delivery of power to the electrical load in response to receiving vacant control signals from both of the occupancy sensors; further wherein
each of the occupancy sensors transmitting a third wireless control signal in response to detecting a continued occupancy condition in the space;
ceasing the delivery of power to the electrical load in response to determining that no wireless control signals have been received from one of the occupancy sensors for the length of a predetermined timeout period, and either receiving a vacant control signal from the other occupancy sensor, or determining that no wireless control signals have been received from the other occupancy sensor for the length of the timeout period;
initializing a failsafe timer with the predetermined timeout period and restarting the failsafe timer in response to receiving the third wireless control signals from the occupancy sensors;
ceasing the delivery of power to the electrical load when the failsafe timer expires; and
wherein the first occupied wireless control signal comprises an occupied-take-action command, and the third wireless control signal comprises an occupied-no-action command.
17. The method of claim 16, wherein the movable structure comprises a door.