论文信息 - Design of the low-temperature AlN interlayer for GaN grown on Si (111) substrate

Design of the low-temperature AlN interlayer for GaN grown on Si (111) substrate

Abstract We have investigated the effect of the thickness and layer number of the low-temperature AlN interlayer (LT-AlN IL) on the stress relaxation and the crystal quality of GaN epilayers grown on Si (1 1 1) substrate by metalorganic chemical vapor deposition. It is found that the stress decreases with the increase of the LT-AlN IL thickness, but the crystal quality of the GaN epilayer goes worse quickly when the LT-AlN IL thickness is larger than 16 nm. This is because the increase of the LT-AlN IL thickness will increase the coalescence thickness of its upper GaN layer, which sensitively affects the crystal quality of the epilayer. Using multiple LT-AlN ILs is an effective method not only to reduce the stress, but also to improve the crystal quality of the GaN epilayer. With the increase of the interlayer number, the probability that dislocations are blocked increases and the probability that dislocations are produced at interfaces decreases. Thus, dislocations in the most upper part of GaN are reduced, resulting in the improvement of the crystal quality. Finally, it is suggested that when the total thickness of the epilayer is fixed, both the thickness and the number of the LT-AlN IL should be carefully designed to reduce the stress and improve the crystal quality of the epilayer simultaneously.

[1] J. Freitas,et al. Properties of Si-doped GaN films grown using multiple AlN interlayers , 1999 .

[2] A. Dadgar,et al. GaN‐based epitaxy on silicon: stress measurements , 2003 .

[3] Armin Dadgar,et al. Thick, crack-free blue light-emitting diodes on Si(111) using low-temperature AlN interlayers and in situ SixNy masking , 2002 .

[4] Xiaohui Wang,et al. Investigation of GaN layer grown on Si(111) substrate using an ultrathin AlN wetting layer , 2002 .

[5] Armin Dadgar,et al. The origin of stress reduction by low-temperature AlN interlayers , 2002 .

[6] Peng Chen,et al. Micro-Raman investigation of strain in GaN and AlxGa1−xN/GaN heterostructures grown on Si(111) , 2002 .

[7] Isamu Akasaki,et al. Effects of ain buffer layer on crystallographic structure and on electrical and optical properties of GaN and Ga1−xAlxN (0 < x ≦ 0.4) films grown on sapphire substrate by MOVPE , 1989 .

[8] Baoshun Zhang,et al. Effect of the N/Al ratio of AlN buffer on the crystal properties and stress state of GaN film grown on Si(111) substrate , 2004 .

[9] Theeradetch Detchprohm,et al. Relaxation Process of the Thermal Strain in the GaN/α-Al2O3 Heterostructure and Determination of the Intrinsic Lattice Constants of GaN Free from the Strain , 1992 .