Semiconductor laser device and method for manufacturing semiconductor laser device

A semiconductor laser device comprising:

• a ridge having an n-type clad layer, a lower-side light confinement layer, and an active layer which are laminated in this order from a lower side;
• current blocking layers embedded on both sides of the ridge, the current blocking layers each having a semi-insulating blocking layer covering a side surface of the ridge, an intermediate blocking layer, and an n-type blocking layer which are laminated in this order from the lower side;
• an upper-side light confinement layer formed on the ridge and the current blocking layers;
• and
• a p-type clad layer formed on the upper-side light confinement layer, wherein
• the ridge has the active layer as an uppermost layer of the ridge, and
• the intermediate blocking layer has a higher energy level at a bottom of a conduction band of the intermediate blocking layer compared to the semi-insulating blocking layer.

A method for manufacturing a semiconductor laser device, the method comprising:

• forming a first semiconductor layer on a substrate, the first semiconductor layer having an n-type clad layer, a lower-side light confinement layer, an active layer, and an upper-side light confinement layer which are laminated in this order from a lower side;
• forming a stripe-like mask on the upper-side light confinement layer;
• etching the first semiconductor layer on both sides of the mask to a halfway position of the n-type clad layer to form a ridge below the mask, the ridge having the upper-side light confinement layer as an uppermost layer of the ridge;
• embedding current blocking layers on both sides of the ridge, the current blocking layers each having a semi-insulating blocking layer covering a side surface of the ridge, an intermediate blocking layer having a higher energy level at a bottom of a conduction band of the intermediate blocking layer compared to the semi-insulating blocking layer and having a lower electron affinity compared to the semi-insulating blocking layer, and an n-type blocking layer which are laminated in this order from the lower side;
• removing the mask;
• and
• forming a second semiconductor layer on the ridge and the current blocking layers, the second semiconductor layer including a p-type clad layer.

A method for manufacturing a semiconductor laser device, the method comprising:

• forming a first semiconductor layer on a substrate, the first semiconductor layer having an n-type clad layer, a lower-side light confinement layer, and an active layer which are laminated in this order from a lower side;
• forming a stripe-like mask on the active layer;
• etching the first semiconductor layer on both sides of the mask to a halfway position of the n-type clad layer to form a ridge below the mask, the ridge having the active layer as an uppermost layer of the ridge;
• embedding current blocking layers on both sides of the ridge, the current blocking layers each having a semi-insulating blocking layer covering a side surface of the ridge, an intermediate blocking layer having a higher energy level at a bottom of a conduction band of the intermediate blocking layer compared to the semi-insulating blocking layer, and an n-type blocking layer which are laminated in this order from the lower side;
• removing the mask;
• and
• forming a second semiconductor layer on the ridge and the current blocking layers, the second semiconductor layer having an upper-side light confinement layer and a p-type clad layer which are laminated in this order from the lower side.