We report the comparative study of both n-SiCN/i-SiCN/p-SiCN and n-SiCN/i-SiCN/p-Si junctions for low-cost and high-temperature UV-detecting applications. The cubic crystalline SiCN films were deposited on p-Si(100) substrate with rapid thermal chemical vapor deposition. At 175 degrees C, the measured current ratio of n-SiCN/i-SiCN/p-SiCN and the n-SiCN/i-SiCN/p-Si junctions with and without irradiation of 254 nm UV light under -5 V and 0.5 mW/cm(2) are 150.26 and 5.42, respectively. Compared to the reported UV detectors with 4H or beta-SiC, the developed n-SiCN/i-SiCN/p-SiCN homojunction has better current ratio in both room and high temperatures. (c) 2007 The Electrochemical Society.