Buried heterostructure semiconductor laser and method of manufacture

A method of fabricating a heterostructure device, comprising:

• growing epitaxial layers of a substrate of first dopant type, an active region and a layer of second dopant type;
• patterning a mask and etching a narrow mesa through the active region and layer of second dopant type using in-situ MOCVD;
• growing a plurality of current blocking layers using in-situ MOCVD and without exposure to oxygen;
• removing the mask and growing an overclad layer and a contact layer of second dopant type;
• etching an isolation mesa through the active region, layer of second dopant type and plurality of current blocking layers such that the isolation mesa incorporates the narrow mesa;
• and
• depositing metal contact layers.

A wafer of heterostructure devices, comprising:

• a plurality of heterostructure devices arranged in pairs, each heterostructure device including
• a substrate of first dopant type,
• an active region, and
• a layer of second dopant type epitaxially grown on the substrate;
• a narrow mesa having less than 20% open area and a side wall slope of less than 85 degrees, wherein said narrow mesa is etched through the active region and layer of second dopant type using in-situ MOCVD;
• a plurality of current blocking layers;
• an overclad layer and a contact layer of second dopant type;
• and
• an isolation mesa incorporating the narrow mesa, wherein the isolation mesa is etched through the active region, layer of second dopant type and plurality of current blocking layers, wherein each pair of heterostructure devices is separated by an unetched area.