Method of forming p-type compound semiconductor layer

A method of forming a p-type compound semiconductor layer, the method comprising the steps of:

• increasing a temperature of a substrate loaded into a reaction chamber to a first temperature;
• supplying a source gas of a Group III element, a source gas of a p-type impurity and a source gas of nitrogen containing hydrogen into the reaction chamber so as to grow the p-type compound semiconductor layer;
• after the growth of the p-type compound semiconductor layer is completed, stopping the supply of the source gas of the Group III element and the source gas of the p-type impurity and lowering the temperature of the substrate to a second temperature;
• growing an ITO tunnel layer by supplying the source gas of the Group III element, a source gas of an n- or p-type impurity and the source gas of nitrogen containing hydrogen;
• after the growth of the ITO tunnel layer is completed, stopping the supply of the source gas of the Group III element and the source gas of the n- or p-type impurity;
• lowering the temperature of the substrate to a third temperature, and stopping the supply of the source gas of nitrogen containing hydrogen;
• and
• lowering the temperature of the substrate to room temperature.