Extended wavelength lasers having a restricted growth surface and graded lattice mismatch

A semiconductor structure, said semiconductor structure comprising:

• a first layer, said first layer having a restricted growth surface having a transverse dimension D, said first layer having a first lattice constant L.sub.1 ;
• a first, last and at least one intermediate transition layers, said transition layers forming a transition region, said transition region disposed above said first layer, said transition region having a vertical thickness T, and where at least one of said intermediate transition layers has lattice constants between L.sub.1 and a second lattice constant L.sub.2 where said first transition layer has a lattice constant closer to said L.sub.1 than L.sub.2 and said last transition layer has a lattice constant closer to said L.sub.2 than L.sub.1 ;
• and
• a second layer disposed on said transition region, said second layer having said second lattice constant L.sub.2 ;
• wherein:
• said transition region has an average fractional change in lattice characterized by .kappa. where .kappa.=(D/T){(L.sub.2 -L.sub.1)/L.sub.1 }, where 0<.vertline..kappa..vertline..ltoreq.10.

A semiconductor structure grown on a substrate having a transverse dimension .gtoreq.21 mm, said semiconductor structure comprising:

• a first layer, said first layer having a restricted growth surface having a transverse dimension D, said first layer having a first lattice constant L.sub.1 ;
• a first, last and at least one intermediate transition layers, said transition layers forming a transition region, said transition region disposed above said first layer, said transition region having a vertical thickness T, and where at least one of said intermediate transition layers has lattice constants between L.sub.1 and a second lattice constant L.sub.2, where said first transition layer has a lattice constant closer to said L.sub.1 than L.sub.2 and said last transition layer has a lattice constant closer to said L.sub.2 than L.sub.1 ;
• and
• a second layer disposed on said transition layer, said second layer a second lattice constant L.sub.2 ;
• wherein:
• said second layer has a transverse dimension D.sub.2, where D.sub.2 =D+D{(L.sub.2 -L.sub.1)/L.sub.1 }.

A semiconductor structure grown on a substrate having a transverse dimension .gtoreq.21 mm, said semiconductor structure comprising:

• a first layer, said first layer having a restricted growth surface having a transverse dimension D, said first layer having a first lattice constant L.sub.1 ;
• a first, last and at least one intermediate transition layers, said transition layers forming a transition region, said transition region disposed above said first layer, said intermediate transition region having a vertical thickness T, and where at least one of said transition layers has lattice constants between L.sub.1 and a second lattice constant L.sub.2, where said first transition layer has a lattice constant closer to said L.sub.1 than L.sub.2 and said last transition layer has a lattice constant closer to said L.sub.2 than L.sub.1 ;
• and
• a second layer disposed on said transition region, said second layer having said second lattice constant L.sub.2 ;
• wherein
• said transition region having an average fractional change in lattice constant characterized by .kappa. where .kappa.=(D/T){(L.sub.2 -L.sub.1)/L.sub.1 }, where D.gtoreq.1 .mu.m and the lattice mismatch between L.sub.1 and L.sub.2 is defined by (L.sub.2 -L.sub.1)/L.sub.1 and is .gtoreq.3.times.10.sup.2 and 0<.kappa..ltoreq.100.

A semiconductor structure grown on a substrate having a transverse dimension .gtoreq.21 mm, said semiconductor structure comprising:

• a first layer, said first layer having a restricted growth surface having a transverse dimension D, said first layer having a first lattice constant L.sub.1 ;
• a first, last and at least one intermediate transition layers, said transition layers forming a transition region, said transition region disposed above said first layer, said transition region having a vertical thickness T, and where at least one of said intermediate transition layers has lattice constants between L.sub.1 and a second lattice constant L.sub.2, where said first transition layer has a lattice constant closer to said L.sub.1 than L.sub.2 and said last transition layer has a lattice constant closer to said L.sub.2 than L.sub.1 ;
• and
• a second layer disposed on said transition region, said second layer having said second lattice constant L.sub.2 ;
• wherein:
• said second layer has a thickness .gtoreq.1.2CT, where:
• CT=(0.4374/f)›In(CT/4)+1!,
• where f is an average lattic mismatch of said second layer normalized to a lattice constant of said substrate;
• and
• said transition region having an average fractional change in lattice constant characterized by .kappa. where .kappa.=(D/T){(L.sub.2 -L.sub.1)/L.sub.1 }, where the lattice mismatch is defined by {(L.sub.2 -L.sub.1)/L.sub.1 }, and where both D and said lattice mismatch are selected from region to the right of and including a line defined by Log D.gtoreq.-3.5 Log {(L.sub.2 -L.sub.1)/L.sub.1 }-6, where D is measured in .mu.m.