Abstract: To provide an elemental technique for improving the emission intensity of deep ultraviolet light from a light emitting layer made of an AlGaInN-based material, in particular, an AlGaN-based material. First, an AlN layer is grown on a sapphire surface. The AlN layer is grown under a NH3-rich condition. The TMAl pulsed supply sequence includes growing an AlGaN layer for 10 seconds, interrupting the growth for 5 seconds to remove NH3, and then introducing TMAl at a flow rate of 1 sccm for 5 seconds. After that, the growth is interrupted again for 5 seconds. Defining this sequence as one growth cycle, five growth cycles are carried out. By such growth, an AlGaN layer having a polarity of richness in Al can be obtained. The above sequence is described only for illustrative purposes, and various variations are possible. In general, the Al polarity can be achieved by a process of repeating both growth interruption and supply of an Al source.

Abstract: Because of a large lattice mismatch between a sapphire substrate and a group III-V compound semiconductor, a good crystal is difficult to grow. A high-quality AlN buffer growth structure A on a sapphire substrate includes a sapphire (0001) substrate 1, an AlN nucleation layer 3 formed on the sapphire substrate 1, a pulsed supplied AlN layer 5 formed on the AlN nucleation layer 3, and a continuous growth AlN layer 7 formed on the pulsed supplied AlN layer 5. Formed on the continuous growth AlN layer 7 is at least one set of a pulsed supplied AlN layer 11 and a continuous growth AlN layer 15. The AlN layer 3 is grown in an initial nucleation mode which is a first growth mode by using an NH3 pulsed supply method. The pulsed supplied AlN layer 5 is formed by using NH3 pulsed supply in a low growth mode which is a second growth mode that increases a grain size and reduces dislocations and therefore is capable of reducing dislocations and burying the nucleation layer 3.

Abstract: To provide an elemental technique for improving the emission intensity of deep ultraviolet light from a light emitting layer made of an AlGaInN-based material, in particular, an AlGaN-based material. First, an AlN layer is grown on a sapphire surface. The AlN layer is grown under a NH3-rich condition. The TMAl pulsed supply sequence includes growing an AlGaN layer for 10 seconds, interrupting the growth for 5 seconds to remove NH3, and then introducing TMAl at a flow rate of 1 sccm for 5 seconds. After that, the growth is interrupted again for 5 seconds. Defining this sequence as one growth cycle, five growth cycles are carried out. By such growth, an AlGaN layer having a polarity of richness in Al can be obtained. The above sequence is described only for illustrative purposes, and various variations are possible. In general, the Al polarity can be achieved by a process of repeating both growth interruption and supply of an Al source.

Abstract: To provide an elemental technique for improving the emission intensity of deep ultraviolet light from a light emitting layer made of an AlGaInN-based material, in particular, an AlGaN-based material. First, an AlN layer is grown on a sapphire surface. The AlN layer is grown under a NH3-rich condition. The TMAl pulsed supply sequence includes growing an AlGaN layer for 10 seconds, interrupting the growth for 5 seconds to remove NH3, and then introducing TMAl at a flow rate of 1 sccm for 5 seconds. After that, the growth is interrupted again for 5 seconds. Defining this sequence as one growth cycle, five growth cycles are carried out. By such growth, an AlGaN layer having a polarity of richness in Al can be obtained. The above sequence is described only for illustrative purposes, and various variations are possible. In general, the Al polarity can be achieved by a process of repeating both growth interruption and supply of an Al source.

Abstract: Because of a large lattice mismatch between a sapphire substrate and a group III-V compound semiconductor, a good crystal is difficult to grow. A high-quality AlN buffer growth structure A on a sapphire substrate includes a sapphire (0001) substrate 1, an AlN nucleation layer 3 formed on the sapphire substrate 1, a pulsed supplied AlN layer 5 formed on the AlN nucleation layer 3, and a continuous growth AlN layer 7 formed on the pulsed supplied AlN layer 5. Formed on the continuous growth AlN layer 7 is at least one set of a pulsed supplied AlN layer 11 and a continuous growth AlN layer 15. The AlN layer 3 is grown in an initial nucleation mode which is a first growth mode by using an NH3 pulsed supply method. The pulsed supplied AlN layer 5 is formed by using NH3 pulsed supply in a low growth mode which is a second growth mode that increases a grain size and reduces dislocations and therefore is capable of reducing dislocations and burying the nucleation layer 3.