半極性氮化銦材料成長與分析

Growth and Characterization of Semi-Polar InN Materials

陳維鈞(Wei-Chun Chen)；郭守義(Shou-Yi Kuo)；賴芳儀(Fang-I Lai)；蕭健男(Chien-Nan Hsiao)

科儀新知

208期（2016 / 09 / 01）

85 - 102

繁體中文

氮化銦為一直接能隙半導體，其能隙約為0.7 eV，適合應用於紅外光區之光電元件中，因沿C軸生長之極性InN具有較大的自發性極化效應，會降低電子電洞的複合機率，因此可利用半極性或非極性InN，增加光電效率。半極性InN之研究中，以鋁酸鑭(LaAIO_3，LAO)(112)單晶做為基板，在不同溫度成長半極性InN(1013)薄膜。當半極性InN薄膜沉積在510°C時有最佳結晶性，其(1013)與(0002)半高寬分別約為1408與1830 arsec，且會有兩組180度對稱之晶域(Domain)，其磊晶關係為(1013)_(InN) // (112)_(LAO)與[1210]_(InN) // [111]_(LAO)。另外，LAO與InN之間有極低晶格不匹配率([1210]_(InN)方向約為-7.75%，[3032]_(InN)方向約為0.2%)，電性方面，半極性InN成長溫度於510°C有最高之電子遷移率與最低載子濃度。光學特性經由PL光譜在10K量測結果顯示，NBE訊號範圍約為0.72至0.81 eV。在510°C所沉積之InN在所有的樣品中有最強的放射訊號與窄的半高寬值。因此，本研究主要在探討半極性InN生長於(112)鋁酸鑭(LaAIO_3，LAO)單晶基板上時所呈現出不同的光電與顯微結構特性。藉由其展現之光電與顯微結構之特性與行為便瞭解薄膜成長機制，有助於提升InN-based磊晶薄膜之品質。

InN material is a direct energy gap semiconductor which is potential for optoelectronics and electronics application. Semipolar InN(1013) films were prepared on LaAIO_3(112) substrate by varying the substrate temperature. The results show that semipolar InN(1013) layers can be grown at 510 °C with the (0002) FWHMs value of 1830 arcsec and (1013) XRC FWHMs value of 1408 arcsec. Also, the InN film is in epitaxy with LAO substrate with orientation relationships of InN(1013) // LAO(112) and [1210]_(InN) // [111]_(LAO). The lattice mismatch between InN and LAO can then be estimated to be 7.75 % along the [1210]_(InN) direction and 0.2 % along the [3032]_(InN) direction. Electronic properties showed that the InN film grown at 510 °C exhibits the highest electron mobility of 494 cm^2/V-s and lowest carrier concentration of 2.4 x 10^(19) cm^(-3). PL spectra at 10 K showed the peaks of near band-edge emission at energies between 0.72 - 0.81 eV. However, InN grown at 510 °C has the highest peak intensity and the narrowest FWHM of these samples which has better quality.