27 1 2006 1 CHIN ESE J OURNAL OF SEMICONDUCTORS Vol. 27 No. 1 Jan.,2006 MEMS 3 1 1 1 1 1,g 2 2 2 2 (1, 100029) (2, 230037) : Au L PCVD SiN x, MEMS (27147 )., (N ETD),N ETD 200m K. : ; ; ; ; ; PACC : 4283 EEACC : 2575B ; 2575F : TN405 : A : 025324177 (2006) 0120150206 1 ( M EMS) [1 4 ].,. K [5 ],. ( FPA),. FPA,,.,,,,,,,. FPA, [1 4 ], ( Si) 2 3 m,.,.,, 40 %, ;,,, [6 ]. [1 4 ], (N ETD) 1 K., 2004 FPA Si FPA, 200 7 K [7 ]. Si, : (1), ; (2),,. FPA,,., 3 ( :60236010) ( :2005AA404210) g. Email :chendp @sohu. com 2005207222,2005209201 ν 2006
1 : M EMS 151, FPA,,N ETD 200m K. 2 :., : (1) ; (2) ; (3), ; (4), ; (5) ; (6) KO H. 1 [2 ], SiN x SiO2, Au Al. SiO2 Al, L PCVD SiN x Au.,, SiN x,. 1 Table 1 Mechanical and thermal properties of several materials used usually SiN x Au SiO2 Al / GPa 180 73 46 92 80 / (W m - 1 K - 1 ) 5. 5 0. 5 296 1. 1 237 / 10-6 K - 1 0. 8 14. 2 0. 05 12. 3 23. 6 / (J kg - 1 K - 1 ) 691 129 908 / (1000kg m - 3 ) 2. 40 19. 3 2. 2 2. 70 1 [2 ] SiN x,, SiN x 8 14 m ( ). 3 Si Nx SiN x M EMS 1 L PCVD SiN x ( n) ( k) Fig. 1 Real ( n) and imaginary ( k) parts of refractive index of L PCVD SiN x,,. (015 2 m) (20mm 20mm), (L PCVD) SiN x. p 100 Si. Si, SiN x, Si H2 Cl2 N H3,, SiN x., Si Si, Si Si, SiN x., 10 7 10 8 Pa ( 2 )., SiN x ;. ( TEM), 2 TEM, TEM 2. SiN x [8 ] (10nm) Si. 4 FPA FPA 100 100,. 200 m 200 m, 20mm 20mm.,.
152 27 3 Fig. 3 Main steps of fabrication process of FPA 2 SiN x TEM (a) (b) Fig. 2 TEM micrograph (a) and planar stress distri2 bution graph (b) of substrate2free SiN x film SiN x / Au, SiN x, Au ;, SiN x / Au, SiN x. Au, [6 ]. 3, 4 FPA SEM,. 4 FPA. Fig. 4 SEM micrograph of a part of the FPA Top2right inserted photo shows structure of one pixel clearly. 5 5. 1, 5. FPA,, CCD, FPA CCD. 5. 2 FPA 5 Fig. 5 Schematic diagram of optical readout system, f / 017, FPA, FPA
1 : M EMS 153 ( 1Pa). 6. 1m, 5m.,,,.. 6 Fig. 6 IR images of a person and his hand 5. 3 N ETD. Ts ( N ) ( N noise), : N ETD = Ts N noise N = N noise N/ Ts N/ Ts,. N noise : (1) N noise : 32, 7. (1), N noise. 5 ; (2) : ( ),. ( 2), 27147 ; 5 35 ; Ts 7153. 5 6 3 3, 6, N ( 3), 194. 2 Table 2 Temperature of background measured by three thermometers / 27. 9 27. 5 27 3 FPA Table 3 Gray level of the pixels for testing 1 2 3 4 5 6 213 211 167 152 183 238 7 Fig. 7 Noise distribution of system ( 1), N Ts, N ETD 01194 K; N 152, N ETD 01247 K; N 238,N ETD 01158 K., N ETD 200m K, N ETD
154 27 158m K, 247m K,.,,. 5. 4 6, ( ),,.., FPA. SiN x Au,,. 1, SiO2 SiN x, SiO2 / Al,SiO2 / Au, SiN x/ Al SiN x / Au. [6 ],, SiN x / Au, SiO2 Al,.,.,,., [6 ] : = 6 ( 2-1 ) T ( n + 1/ P) L 2 / h1 (2) ; ; L ; h ; T ; n. P = ( n2 < - 1) 2 + 4 n( n 2 + 2 n + 1) < (3) n< <= E2 / E1, E. (2) (3),,,,.,,., 2 m SiN x 012 m Au,.. 6 M EMS,. N ETD 200m K.,. [ 1 ] Mao M, Perazzo T, Kwon O,et al. Direct2view uncooled mi2 cro2optomechanical infrared camera. Twelfth IEEE Interna2 tional Conference on MEMS,1999 :100 [ 2 ] Zhao Y. Optomechanical uncooled infrared imaging system. Dissertation of UC,Berkeley,2002 [ 3 ] Ishizuya T,Suzuki J,Akagawa K,et al. 160 120 pixels opti2 cally readable biomaterial infrared detector. Proc IEEE MEMS,2002 :578 [ 4 ] Duan Zhihui, Zhang Qingchuan, Wu Xiaoping, et al. Un2 cooled optical readable biomaterial micro2cantilever infrared imaging device. Chinese Physics Letters,2003,20 (12) :2130 [ 5 ] Lai J,Perazzo T,Shi Z,et al. Optimization and performance of high2resolution micro2optomechanical t hermal sensors. Sen2 sors and Act uators A,1997,58 :113 [ 6 ] Pan Liang. Focus plane array and readout system based on MEMS and visible light. Dissertation of USTC,2004 (in Chi2 nese) [. MEMS.,2004 ] [ 7 ] Pan Liang, Zhang Qingchuan, Wu Xiaoping, et al. MEMS based optomechanical infrared imaging. Experimental Me2 chanics,2004,19 (4) :403 (in Chinese) [,,,. MEMS.,2004,19 (4) : 403 ] [ 8 ] Chen Dapeng, Ye Tianchun, Xie Changqing, et al. Stress in SiNx film embedded with silicon nanocrystals preparing by L PCVD. Chinese Journal of Semiconductors, 2001, 22 ( 12) : 1529 (in Chinese) [,,,. L PCVD.,2001,22 (12) :1529 ]
1 : M EMS 155 A MEMS Based Focus Plane Array for Infrared Imaging 3 Li Chaobo 1, Jiao Binbin 1, Shi Shali 1, Ye Tianchun 1, Chen Dapeng 1,g, Zhang Qingchuan 2, Guo Zheying 2, Dong Fengliang 2, and Wu Xiaoping 2 (1 Micro2Processing and N ano2technology Department, Institute of Microelectronics, Chinese A cadem y of Sciences, B ei j ing 100029, China) (2 Key L aboratory of Mechanical Behavior and Desi gn of M aterials, Universit y of Science and Technology of China, Hef ei 230027, China) Abstract : Based on the opto2mechanical effect and M EMS technology, a novel substrate2f ree FPA with a thermally isolated structure for uncooled inf rared imaging is developed. Alternately evaporating Au on a SiN x cantilever is used for thermal isola2 tion. A human s thermal image is obtained successfully using the inf rared imaging system composed of the FPA and optical de2 tection system. Experimental result s show that the realization of thermal isolation in the substrate2f ree FPA increases the tem2 perature of the deflecting leg effectively,while the N ETD is about 200m K. Key words : M EMS ; FPA ; opto2mechanical ; L PCVD ; SiN x ; N ETD PACC : 4283 EEACC : 2575B ; 2575F Article ID : 025324177 (2006) 0120150206 3 Project supported by the National Natural Science Foundation of China (No. 60236010) and the National High Technology Research and De2 velopment Program of China (No. 2005AA404210) g Corresponding author. Email :chendp @sohu. com Received 22 J uly 2005,revised manuscript received 1 September 2005 ν 2006 Chinese Institute of Electronics