1. Power Semiconductor Devices for Low-Temperature Environments Space Power Workshop 2004 21 April 2004, Manhattan Beach, California

2. 2 R. R. Ward, W. J. Dawson, L. Zhu, R. K. Kirschman GPD Optoelectronics Corp., Salem, New Hampshire O. Mueller, M. J. Hennessy, E. K. Mueller MTECH Laboratories, Ballston Lake, New York R. L. Patterson, J. E. Dickman NASA Glenn Research Center, Cleveland, Ohio A. Hammoud QSS Group Inc., Cleveland, Ohio Supported by NASA Glenn Research Center and ONR/DARPA

3. 3 Outline Why low-temperature electronics for space? Semiconductor materials options Development program Designs and results Diodes: Ge & SiGe FETs: Ge MISFETs, Ge JFETs & Ge SITs Bipolars: Ge BJTs & SiGe HBTs Summary Future

4. 4 Outline Why low-temperature electronics for space? Semiconductor materials options Development program Designs and results Diodes: Ge & SiGe FETs: Ge MISFETs, Ge JFETs & Ge SITs Bipolars: Ge BJTs & SiGe HBTs Summary Future

5. 5 Temperatures for Spacecraft

6. 6 Solar System Temperatures

7. 7 Benefits of Using Low-Temp Electronics Reduce mass & volume Reduce power requirements Reduce spacecraft complexity Reduce disruption of environment Increase operating/mission time Increase overall reliability

8. 8 Outline Why low-temperature electronics for space? Semiconductor materials options Development program Designs and results Diodes: Ge & SiGe FETs: Ge MISFETs, Ge JFETs & Ge SITs Bipolars: Ge BJTs & SiGe HBTs Summary Future

9. 9 Semiconductor Materials Comparison

10. 10 Outline Why low-temperature electronics for space? Semiconductor materials options Development program Designs and results Diodes: Ge & SiGe FETs: Ge MISFETs, Ge JFETs & Ge SITs Bipolars: Ge BJTs & SiGe HBTs Summary Future

11. 11 Development Program Develop semiconductor devices: diodes and transistors Specifically designed for low temperatures For use down to 30 K ( ~ –240°C) and lower For spacecraft Power Management and Actuator Control

12. 12 Outline Why low-temperature electronics for space? Semiconductor materials options Development program Designs and results Diodes: Ge & SiGe FETs: Ge MISFETs, Ge JFETs & Ge SITs Bipolars: Ge BJTs & SiGe HBTs Summary Future

13. 13 Ge Low-Temperature Power Diodes P- - N Bulk Design N– ( ) N+ implant P+ implantMetal Guard ring(s)

14. 14 Ge LT Power Diodes - Forward

15. 15 Ge LT Power Diodes - Forward

16. 16 Ge LT Power Diodes - Forward I-V

17. 17 Ge LT Power Diode - Forward I-V

18. 18 Ge Power Diodes - Reverse Breakdown

19. 19 Ge Power Diodes - Reverse Recovery

20. 20 Ge Power Diodes - Reverse Recovery

21. 21 Ge Power Diodes - Reverse Recovery

22. 22 Outline Why low-temperature electronics for space? Semiconductor materials options Development program Designs and results Diodes: Ge & SiGe FETs: Ge MISFETs, Ge JFETs & Ge SITs Bipolars: Ge BJTs & SiGe HBTs Summary Future

23. 23 SiGe LT Power Diodes - Design (N+ implant) P+ SiGe Metal N– Si epi N+ Si

24. 24 SiGe vs Si Power Diodes - Forward

25. 25 SiGe vs Si Power Diodes - Forward

26. 26 SiGe LT Power Diodes - Forward

27. 27 SiGe LT Power Diodes - Forward

28. 28 SiGe LT Power Diodes - Forward

29. 29 SiGe LT Power Diodes - Reverse

30. 30 SiGe LT Power Diodes - Reverse

31. 31 SiGe LT Power Diodes - Reverse Recovery

32. 32 SiGe LT Power Diodes - Reverse Recovery

33. 33 Outline Why low-temperature electronics for space? Semiconductor materials options Development program Designs and results Diodes: Ge & SiGe FETs: Ge MISFETs, Ge JFETs & Ge SITs Bipolars: Ge BJTs & SiGe HBTs Summary Future

34. 34 Ge LT Power JFET or MISFET ~1.8 mm G S D S G

35. 35 Lateral Ge MISFET Design Substrate contact Source Gate P+ implant P substrate Gate dielectric N+ implant Drain

36. 36 Ge Power MISFET at +20°C 20 V 1 A ΔV GS = 1 V/step

37. 37 Ge Power MISFET at –196°C (77 K) 20 V 1 A ΔV GS = 1 V/step

38. 38 Ge Power MISFET at –269°C (4 K) 20 V 1 A ΔV GS = 1 V/step

39. 39 Ge MISFET Switching - 50 kHz ~ 30  Load

40. 40 Ge MISFET Switching - 5 MHz ~ 30  Load

41. 41 Outline Why low-temperature electronics for space? Semiconductor materials options Development program Designs and results Diodes: Ge & SiGe FETs: Ge MISFETs, Ge JFETs & Ge SITs Bipolars: Ge BJTs & SiGe HBTs Summary Future

42. 42 Ge JFET Cross-Section (n-channel) Back gate contact Source Front gate P+ implant P+ substrate N epitaxial layer N+ implant Drain P+ implant

43. 43 Power Ge JFET at +20°C 10 V 2 A ΔV GS = 1 V/step

44. 44 Power Ge JFET at –196°C (77 K) 10 V 2 A ΔV GS = 1 V/step

45. 45 Power Ge JFET at –269°C (4 K) 10 V 2 A ΔV GS = 1 V/step

46. 46 Another Power Ge JFET at –253°C (20 K) 10 V 1 A ΔV GS = 1 V/step

47. 47 Power Ge JFET at +20°C 50 V 1 A ΔV GS = 1 V/step

48. 48 Power Ge JFET at –196°C (77 K) 50 V 1 A ΔV GS = 1 V/step

49. 49 Power Ge JFET at –269°C (4 K) 50 V 1 A ΔV GS = 1 V/step

50. 50 Outline Why low-temperature electronics for space? Semiconductor materials options Development program Designs and results Diodes: Ge & SiGe FETs: Ge MISFETs, Ge JFETs & Ge SITs Bipolars: Ge BJTs & SiGe HBTs Summary Future

51. 51 Ge SIT (Static Induction Transistor) Drain Source Gate N+ implant N– substrate P implant N+ implant

52. 52 Ge SIT - FET-Like Region

53. 53 Ge SIT - Triode-Like Region

54. 54 Outline Why low-temperature electronics for space? Semiconductor materials options Development program Designs and results Diodes: Ge & SiGe FETs: Ge MISFETs, Ge JFETs & Ge SITs Bipolars: Ge BJTs & SiGe HBTs Summary Future

55. 55 Ge Bipolar - Double-Implant Collector Base Emitter N+ implant N– substrate P implant N+ implant

56. 56 Ge BJT at +20°C 10 V 0.1 A ΔI B = 0.5 mA/step

57. 57 Ge BJT at –196°C (77 K) 10 V 0.1 A ΔI B = 1 mA/step

58. 58 Ge and Si Bipolar Comparison

59. 59 Outline Why low-temperature electronics for space? Semiconductor materials options Development program Designs and results Diodes: Ge & SiGe FETs: Ge MISFETs, Ge JFETs & Ge SITs Bipolars: Ge BJTs & SiGe HBTs Summary Future

60. 60 SiGe HBT (Heterojunction Bipolar Transistor) ~0.5 μm n+ Si ~0.4 μm p SiGe ~20 μm n– Si Emitter contact ~300 μm n+ Si Collector contact Base contact

61. 61 SiGe HBT at +20°C 20 V 0.2 A ΔI B = 1 mA/step

62. 62 SiGe HBT at –196°C (77 K) 50 V ΔI B = 0.5 mA/step 0.2 A

63. 63 Outline Why low-temperature electronics for space? Semiconductor materials options Development program Designs and results Diodes: Ge & SiGe FETs: Ge MISFETs, Ge JFETs & Ge SITs Bipolars: Ge BJTs & SiGe HBTs Summary Future

64. 64 Summary Electronics capable of low-temperature operation will be important for spacecraft (cold environments and space observatories) We have been developing semiconductor devices for operation down to ~20 K (~ –250°C) We are basing the devices on Ge and SiGe We have developed Ge low-temperature power diodes, junction field-effect transistors (JFETs), and metal-insulator- semiconductor field-effect transistors (MISFETs) We are in process of developing SiGe low-temperature power diodes, metal-insulator-semiconductor field-effect transistors (MISFETs), and heterostructure bipolar transistors (HBTs)

65. 65 Outline Why low-temperature electronics for space? Semiconductor materials options Development program Designs and results Diodes: Ge & SiGe FETs: Ge MISFETs, Ge JFETs & Ge SITs Bipolars: Ge BJTs & SiGe HBTs Summary Future

66. 66 Future Continue to develop low-temperature power SiGe diodes, SiGe bipolar transistors, SiGe MOS field-effect transistors Investigate low-temperature power SiGe IGBTs Proposed development of low-temperature power thyristors (SCRs)