一种应用于MOCVD的3波长在线红外测温方法

Three-wavelength on-line infrared thermometry for MOCVD

根据金属有机物化学气相沉积(MOCVD)在线红外测温的发展需要,提出一种3波长免探测孔有效面积校准和反射率修正的测温方法。给出了探测1 300nm、1 150nm、940nm 3波长的在线测温探头设计方案和光路图,将该探头应用于THOMAS SWAN CCS MOCVD 5.08cm(2英寸)Si(111)衬底上生长10μm GaN外延层的在线测温。测量结果表明:在700℃~1 100℃范围内,探头多次测量的重复性误差在1.0℃内,在950℃~1 100℃范围内,以EpiTT红外测温仪为参考,探头测温精度在1℃内,距离容差性为2mm。该探头应用于我国自主研发的MOCVD 5.08cm Si(111)衬底上生长InGaN/GaN MQW结构蓝光LED外延片,可得最低测温量程为435℃,nGaN生长过程中测量噪声为0.75℃。结果分析表明:该3波长免修正在线红外测温法对于高质量单层薄膜外延生长具有一定可行性,对于多层复杂结构外延生长需要进一步改进。

According to the development needs of on-line infrared thermometry of metal organic chemical vapor deposition（MOCVD）, a three-wavelength infrared thermometry is proposed, which can avoid the calibration of the effective area of detector hole and the modification of re- flectivity. The design scheme of the three-wavelength （1 300 nm, 1 150 nm,940 nm） on-line in- frared thermometry probe and the light path are presented. The probe is used in the 5.08 cm（2 inch） silicon （111） substrate growing 10 μm GaN epitaxial wafer in THOMAS SWAN CCS MOCVD system. Result shows that the accuracy is within 1℃ in the range from 950℃ to 1 100℃ ,referring to the EpiTT infrared thermometry. The repeatability is within 1.0℃ from 700℃ to 1 100℃. The distance tolerance is 2 mm. Moreover,the probe is used in the 5.08 cm silicon （111） substrate growing blue light LED epitaxial wafer with InGaN/GaN MQW structure in homemade MOCVD system. Result shows that the lowest range of the probe is equally 435℃. The measurement noise of n-GaN layer during growing is at 0.75℃. The analysis of the measured results indicate that the method for single layer thin film epitaxial growth has the cer- tain practicability,however, further improvements are needed for the multi-layer complex structure epitaxial growth.