1. A semiconductor-based structure, comprising:
a first tensilely strained layer consisting essentially of silicon;
a second tensilely strained layer consisting essentially of silicon, and
a compressively strained layer associated with a p-channel, and consisting essentially of silicon and germanium disposed between and in contact with the first and second tensilely strained layers, the first and second tensilely strained layers impeding diffusion of germanium out of the compressively strained layer.
2. The semiconductor-based structure of claim 1, further comprising a strain-inducing substrate in contact with the first tensilely strained layer, and wherein the first tensilely strained layer has a thickness selected to support an n-type channel.
3. The semiconductor-based structure of claim 2, wherein the thickness is in a range of about 5 nm to about 20 nm.
4. The semiconductor-based structure of claim 2, wherein the second tensilely strained layer has a thickness that is insufficient to support an effective n-type channel.
5. The semiconductor-based structure of claim 2, wherein the thickness of the second tensilely strained layer is in a range of about 1 nm to less than 7 nm.
6. The semiconductor-based structure of claim 1, further comprising a strain-inducing substrate in contact with the first tensilely strained layer, and wherein the first tensilely strained layer has a thickness greater than a diffusion length of germanium.
7. The semiconductor-based structure of claim 1, further comprising a strain-inducing substrate in contact with the first tensilely strained layer, and wherein the first tensilely strained layer has a thickness less than a thickness of the second tensilely strained layer.
8. The semiconductor-based structure of claim 7, wherein the thickness of the first tensilely strained layer is less than about 1.5 nm.
9. The semiconductor-based structure of claim 1, further comprising a strain-inducing substrate in contact with the first tensilely strained layer, and a NMOS component comprising a gate dielectric layer adjacent to the first tensilely strained layer, and a gate in contact with the gate dielectric layer for mediation of a n-type channel formed in at least one of the first and second tensilely strained layers.
10. The semiconductor-based structure of claim 9, wherein the n-type channel is formed at least mostly in the second tensilely strained layer.
11. The semiconductor-based structure of claim 9, wherein the gate dielectric layer is in contact with one of the second tensilely strained layer and the compressively strained layer.
12. The semiconductor-based structure of claim 11, further comprising a PMOS component comprising a gate dielectric layer adjacent to the compressively strained layer, and a gate in contact with the gate dielectric layer for mediation of a p-type channel at least mostly in the compressively strained layer.
13. The semiconductor-based structure of claim 1, further comprising a strain-inducing layer comprising silicon and germanium in contact with the first tensilely strained layer.
14. The semiconductor-based structure of claim 1, further comprising a strain-inducing layer comprising an oxide in contact with the first tensilely strained layer.
15. A semiconductor-based structure, comprising:
a substrate layer;
a compressively strained semiconductor layer adjacent to the substrate layer to provide a channel for a component; and
a tensilely strained semiconductor layer disposed between the substrate layer and the compressively strained semiconductor layer, and in contact with the compressively-strained semiconductor layer, the tensilely strained semiconductor layer impeding diffusion of a species out of the compressively strained semiconductor layer.
16. The semiconductor-based structure of claim 15, wherein the compressively strained semiconductor layer consists essentially of silicon and germanium, the tensilely strained semiconductor layer consists essentially of silicon, and the species is germanium.
17. The semiconductor-based structure of claim 15, further comprising a second tensilely strained layer consisting essentially of a third semiconductor in contact with the compressively strained layer on an opposite side of the compressively strained layer relative to the tensilely strained layer.
18. The semiconductor-based structure of claim 15, further comprising at least one PMOS component that primarily utilizes the compressively strained layer for a p-type channel.
19. The semiconductor-based structure of claim 18, further comprising at least one NMOS component that primarily utilizes the tensilely strained layer for a n-type channel.
20. The semiconductor-based structure of claim 15, wherein, for a temperature in a range of about 300\xb0 C. to about 1000\xb0 C., the composition of the tensilely strained layer is selected to provide a diffusivity of Ge in the tensilely strained layer that is less than about 95% of a diffusivity of Ge in the compressively strained layer.
21. A method for making an electronic device, comprising:
providing, on a strain-inducing substrate, a first tensilely strained layer consisting essentially of silicon;
forming a compressively strained layer on the first tensilely strained layer, the compressively strained layer consisting essentially of silicon and germanium; and
forming a second tensilely strained layer on the compressively strained layer, the second tensilely strained layer consisting essentially of silicon.
22. The method of claim 21, wherein the strain-inducing substrate comprises a layer in contact with the first tensilely strained layer, the layer consisting of one of an oxide and relaxed SiGe.
23. The method of claim 22, wherein providing the first tensilely strained layer comprises bonding the first tensilely strained layer to the strain-inducing substrate.
24. The method of claim 21, further comprising removing a portion of the second tensilely strained layer and a portion of the compressively strained layer to at least nearly expose a portion of the first tensilely strained layer, forming a gate dielectric layer adjacent the portion of the first tensilely strained layer, and forming a gate in contact with the gate dielectric layer for mediating a n-type channel in the first tensilely strained layer.
25. The method of claim 24, wherein the gate dielectric layer is in contact with the portion of the first tensilely strained layer.
26. The method of claim 21, further comprising oxidizing at least most of a lateral portion of the second tensilely strained layer, and forming a gate contact of a PMOS component on the oxidized portion.
27. The method of claim 21, further comprising oxidizing at least most of a second lateral portion of the second tensilely strained layer, and forming a gate contact of a NMOS component adjacent to the first strained layer of the lateral portion.
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 drilling mud cooler, comprising:
a first mud heat exchanger that is adapted to receive a flow of drilling mud;
a first closed-loop cooling system that is adapted to cool a first cooling fluid that is circulated through said first mud heat exchanger so as to reduce a temperature of said flow of drilling mud from a first temperature to a second temperature;
a second mud heat exchanger that is adapted to receive said flow of reduced temperature drilling mud from said first mud heat exchanger;
a second closed-loop cooling system that is adapted to cool a second cooling fluid that is circulated through said second mud heat exchanger so as to further reduce said temperature of said flow of drilling mud from said second temperature to a third temperature.
2. The drilling mud cooler of claim 1, wherein said first closed-loop cooling system is adapted to be in a mud cooling standby mode when said first temperature is below a predetermined mud temperature.
3. The drilling mud cooler of claim 1, wherein said first closed-loop cooling system comprises an air cooler that is adapted to cool said first cooling fluid.
4. The drilling mud cooler of claim 3, further comprising a fluid circulation pump that is adapted to circulate said first cooling fluid through said air cooler and said first mud heat exchanger.
5. The drilling mud cooler of claim 3, wherein said air cooler comprises a cooling coil and at least one cooling fan, said at least one cooling fan being adapted to draw a flow of air across said cooling coil while said first cooling fluid is circulated through said cooling coil so as to cool said first cooling fluid after said first cooling fluid has been heated in said first mud heat exchanger by said flow of drilling mud.
6. The drilling mud cooler of claim 1, wherein said second closed-loop cooling system is adapted to be in a mud cooling standby mode when said second temperature is below a predetermined mud temperature.
7. The drilling mud cooler of claim 1, wherein said second closed-loop cooling system comprises an evaporator that is adapted to cool said second cooling fluid.
8. The drilling mud cooler of claim 7, further comprising a fluid circulation pump that is adapted to circulate said second cooling fluid through said evaporator and said second mud heat exchanger.
9. The drilling mud cooler of claim 7, wherein said second closed-loop cooling system comprises at least one refrigeration chiller unit, said at least one refrigeration chiller unit comprising a cooling coil that is adapted to circulate of a flow of a refrigerant through said evaporator while said second cooling fluid is circulated through said cooling coil so as to cool said second cooling fluid after said second cooling fluid has been heated in said second mud heat exchanger by said flow of drilling mud.
10. The drilling mud cooler of claim 9, wherein said at least one refrigeration chiller unit further comprises a compressor, a condensing coil disposed in a condensing unit comprising one or more cooling fans, and at least one of an expansion device and a flash tank.
11. The drilling mud cooler of claim 9, wherein said at least one refrigeration chiller unit is a first refrigeration chiller unit and said cooling coil is a first cooling coil that is adapted by circulating a flow of a first refrigerant through said evaporator, said second closed-loop cooling system further comprising a second refrigeration chiller unit that comprises a second cooling coil that is adapted to circulate of a flow of a second refrigerant through said evaporator while said second cooling fluid is circulated through said second cooling coil so as to further cool said second cooling fluid after said second cooling fluid has been heated in said second mud heat exchanger by said flow of drilling mud.
12. The drilling mud cooler of claim 11, wherein said second refrigeration chiller unit is adapted be in a mud cooling standby mode when said third temperature is below a predetermined mud temperature, and wherein operation of said second refrigeration chiller unit is adapted be initiated when said third temperature is at least at said predetermined mud temperature so as to further cool said second cooling fluid.
13. A system for cooling drilling mud, the system comprising:
a drilling mud cooler comprising first and second stage closed-loop cooling systems thermally coupled to respective first and second stage mud heat exchangers, wherein said drilling mud cooler is adapted to receive a flow of drilling mud having a first mud temperature into said first stage mud heat exchanger and to discharge said flow of drilling mud from said second stage mud heat exchanger at a second temperature that is less than said first temperature; and
a control system that is operatively coupled to said drilling mud cooler, wherein said control system is adapted to sequentially stage operation of said first and second stage closed-loop cooling systems by initiating operation of said first stage closed-loop cooling system so as to cool said flow of drilling mud flowing through said first stage mud heat exchanger when said first temperature rises to at least a first predetermined mud temperature and thereafter initiating operation of said second stage closed-loop cooling system so as to further cool said flow of drilling mud flowing through said second stage mud heat exchanger when said second temperature rises to at least at a second predetermined mud temperature.
14. The system of claim 13, wherein said control system is adapted to maintain said first stage closed-loop cooling system in a mud cooling standby mode when said first temperature is below said first predetermined mud temperature and to maintain said second stage closed-loop cooling system in a mud cooling standby mode when said second temperature is below said second predetermined mud temperature.
15. The system of claim 14, wherein said control system is adapted to operate said first stage closed-loop cooling system under a substantially constant operating capacity while said first temperature is above said first predetermined mud temperature and to return said first stage closed-loop cooling system to said mud cooling standby mode when said first temperature drops below said first predetermined mud temperature.
16. The system of claim 15, wherein said substantially constant operating capacity is a maximum operating capacity of said first stage closed-loop cooling system.
17. The system of claim 13, wherein said drilling mud cooler further comprises a first stage fluid circulation pump and said first stage closed-loop cooling system comprises an air cooler, said first stage fluid circulation pump being adapted to circulate a first stage cooling fluid between said first stage mud heat exchanger and said air cooler.
18. The system of claim 17, wherein said first stage mud heat exchanger is adapted to exchange heat between said flow of drilling mud and said first stage cooling fluid so as to cool said flow of drilling mud and to heat said first stage cooling fluid and said air cooler is adapted to cool said heated first stage cooling fluid flowing from said first stage mud heat exchanger.
19. The system of claim 18, wherein said air cooler comprises a cooling coil and a least one cooling fan, said at least one cooling fan being adapted to draw a flow of air across said cooling coil while said first stage cooling fluid is circulated through said cooling coil so as to cool said heated first stage cooling fluid flowing from said first stage mud heat exchanger.
20. The system of claim 13, wherein said drilling mud cooler further comprises a second stage fluid circulation pump and said second stage closed-loop cooling system comprises a refrigeration system, said second stage fluid circulation pump being adapted to circulate a second stage cooling fluid between said second stage mud heat exchanger and said refrigeration system.
21. The system of claim 20, wherein said second stage mud heat exchanger is adapted to exchange heat between said flow of drilling mud and said second stage cooling fluid so as to further cool said flow of drilling mud and to heat said second stage cooling fluid and said refrigeration system is adapted to cool said heated second stage cooling fluid flowing from said second stage mud heat exchanger.
22. The system of claim 21, wherein said refrigeration system comprises first and second refrigeration chiller units, said control system being adapted to maintain said first and second refrigeration chiller units in a cooling standby mode when said second temperature is below said second predetermined mud temperature and to sequentially stage operation of said first and second refrigeration chiller units so as to cool said heated second stage cooling fluid flowing from said second stage mud heat exchanger when said second temperature rises to at least said second predetermined mud temperature.
23. The system of claim 22, wherein said control system is adapted to sequentially stage operation of said first and second refrigeration chiller units by first initiating operation of said first refrigeration chiller unit so as to lower said second temperature below said second predetermined mud temperature and maintaining said second refrigeration chiller unit in said cooling standby mode until said first refrigeration chiller unit alone is unable to keep said second temperature below said second predetermined mud temperature.
24. The system of claim 23, wherein said control system is adapted to sequentially stage operation of said first and second refrigeration chiller units by gradually ramping up operation of said first refrigeration chiller unit to a predetermined maximum unit operating level as a temperature of said flow of drilling mud exiting said drilling mud cooler increases and thereafter initiating operation of said second refrigeration chiller unit when said second temperature rises to at least said second predetermined mud temperature while said first refrigeration chiller unit is being operated at said predetermined maximum unit operating level.
25. A method for cooling drilling mud, the method comprising:
thermally coupling a first closed-loop cooling system to a first mud heat exchanger;
thermally coupling a second closed-loop cooling system to a second mud heat exchanger;
receiving a flow of drilling mud in said first mud heat exchanger;
controlling operation of said first closed-loop cooling system with a control system so as to cool said flow of drilling mud flowing through said first mud heat exchanger when a first temperature of said flow of drilling mud entering said first mud heat exchanger exceeds a predetermined mud set point temperature;
passing said flow of drilling mud from said first mud heat exchanger to said second mud heat exchanger; and
controlling operation of said second closed-loop cooling system with said control system so as to further cool said flow of drilling mud flowing through said second mud heat exchanger when a second temperature of said flow of drilling mud exiting said second mud heat exchanger exceeds said predetermined mud set point temperature.
26. The method of claim 25, wherein controlling operation of said first closed-loop cooling system with said control system comprises maintaining said first closed-loop cooling system in a mud cooling standby mode when said first temperature is below said predetermined mud set point temperature and initiating operation of said first closed-loop cooling system when said first temperature rises to at least said predetermined mud set point temperature.
27. The method of claim 25, wherein thermally coupling said first closed-loop cooling system to said first mud heat exchanger comprises circulating a first cooling fluid through said first closed-loop cooling system and said first mud heat exchanger.
28. The method of claim 27, wherein cooling said flow of drilling mud flowing through said first mud heat exchanger comprises cooling said first cooling fluid in an air cooler of said first closed-loop cooling system by circulating said first cooling fluid through a cooling coil of said air cooler while drawing a flow of air across said cooling coil with one or more cooling fans of said air cooler.
29. The method of claim 25, wherein controlling operation of said second closed-loop cooling system with said control system comprises maintaining said second closed-loop cooling system in a mud cooling standby mode when said second temperature is below said predetermined mud set point temperature and initiating operation of said second closed-loop cooling system when said second temperature rises to at least said predetermined mud set point temperature.
30. The method of claim 25, wherein thermally coupling said second closed-loop cooling system to said second mud heat exchanger comprises circulating a second cooling fluid through said second closed-loop cooling system and said second mud heat exchanger.
31. The method of claim 30, wherein further cooling said flow of drilling mud flowing through said second mud heat exchanger comprises cooling said second cooling fluid in a refrigeration system of said second closed-loop cooling system by circulating said second cooling fluid through an evaporator of said refrigeration system while circulating a refrigerant through said evaporator in at least one of a plurality of cooling coils comprising said refrigeration system.
32. The method of claim 30, wherein said second closed-loop cooling system comprises first and second refrigeration chiller units, the method further comprising sequentially staging operation of said first and second refrigeration chiller units when said second temperature exceeds said predetermined mud set point temperature.
33. The method of claim 32, wherein sequentially staging operation of said first and second refrigeration chiller units comprises first initiating operation of said first refrigeration chiller unit so as to lower said second temperature below said predetermined mud set point temperature while maintaining said second refrigeration chiller unit in a cooling standby mode, and initiating operation of said second refrigeration chiller unit when said first refrigeration chiller unit alone is unable to keep said second temperature below said second predetermined mud temperature.
34. The method of claim 32, wherein sequentially staging operation of said first and second refrigeration chiller units comprises initiating operation of said first refrigeration chiller while maintaining said second refrigeration chiller unit in a cooling standby mode, gradually ramping up operation of said first refrigeration chiller unit to a predetermined maximum unit operating level as a temperature of said flow of drilling mud exiting said second mud heat exchanger increases, and thereafter initiating operation of said second refrigeration chiller unit while maintaining said first refrigeration chiller unit at said predetermined maximum unit operating level.