Selectively Si-doped InAs/A1AsSb short-period-superlattices as N-type cladding layers for mid-IR laser structures grown on InAs substrates

• US 5,594,750 A
• Filed: 06/06/1995
• Issued: 01/14/1997
• Est. Priority Date: 06/06/1995
• Status: Expired due to Term

• Current Assignee: Hughes Electronics Corporation (Rtx Corporation)
• Original Assignee: Hughes Aircraft Company (Rtx Corporation)
• Inventors: Zhang, Yong H., Chow, David H.
• Primary Examiner(s): Davie, James W.
• Application Number:
  US08/468,179
• Time in Patent Office: 588 Days
• Field of Search: 372/45, 372/44, 372/43, 257/14, 257/15
• US Class Current: 372/45.012
• CPC Class Codes: B82Y 20/00 Nanooptics, e.g. quantum optics or photonic crystals
• CPC Class Codes: H01L 29/155 Comprising only semiconductor materials H01L29/154 takes precedence
• CPC Class Codes: H01S 5/3216 quantum well or superlattice cladding layers
• CPC Class Codes: H01S 5/343 in AIIIBV compounds, e.g. AlGaAs-laser , InP-based laser
• CPC Class Codes: H01S 5/34306 emitting light at a wavelength longer than 1000nm, e.g. InP based 1300 and 1500nm lasers

Abstract

A MWIR laser is provided having a novel n-type superlattice cladding layer comprising either InAs/AlAs₀.16 Sb₀.84 or In_x Ga_y Al_1-x-y As/AlSb. The n-type superlattice cladding layer may comprise a Si selectively-doped (SD) InAs/AlAs₀.16 Sb₀.84 short-period superlattice (SPS) lattice-matched to an InAs substrate or a Si SD In_x Ga_y Al_1-x-y As/AlSb SPS lattice-matched to a GaSb or InAs substrate. The advantages of the Si SD InAs/AlAs₀.16 Sb₀.84 SPS and Si SD In_x Ga_y Al_1-x-y As/AlSb SPS include: (1) large dynamic range in the electron concentration in the Si-doped n-type cladding layer; and (2) strong hole confinement in the active region. Furthermore, the novel n-type superlattice cladding layer can be deposited without the use of tellurium (Te) which is not a preferred source material for MBE growth of III-V semiconductors.

Claims

1. A laser diode capable of operating at mid-wave infrared wavelengths, said laser diode including an active region having a first surface and a second surface and a first p-type cladding layer contacting said second surface and a second n-type cladding layer contacting said first surface, wherein said second n-type cladding layer comprises a plurality of alternating layers of either n-InAs and AlAsSb or n-InGaAlAs and AlSb.

2. The laser diode of claim 1 wherein said plurality of alternating layers in said second n-type cladding layer comprise n-InAs and AlAsSb and said layers of n-InAs are n-doped with silicon or wherein said plurality of alternating layers comprise n-InGaAlAs and AlSb and said layers of n-InGaAlAs are n-doped with silicon.

3. The laser diode of claim 1 wherein said layers of AlAsSb are given by the formula AlAs₀.16 Sb₀.84 or said layers of n-InGaAlAs are given by the formula n-In_x Ga_y Al_1-x-y As, where x is in the range 0<

x≦

1, y is in the range 0≦

y<

1, and x+y≦

1.

4. The laser diode of claim 1 wherein said plurality of alternating layers of n-InAs and AlAsSb are lattice-matched to an InAs substrate.

5. The laser diode of claim 1 wherein said plurality of alternating layers of n-InGaAlAs and AlSb are lattice-matched to a GaSb or InAs substrate.

6. The laser diode of claim 1 wherein said layers of AlAsSb or said layers of AlSb in said second n-type cladding layer are intentionally undoped.

7. The laser diode of claim 1 wherein said first p-type cladding layer comprises a plurality of alternating layers of either p-InAs and p-AlAsSb or p-InGaAlAs and p-AlSb.

8. The laser diode of claim 7 wherein said layers of p-InAs and p-AlAsSb or said layers of p-InGaAlAs and p-AlSb in said first p-type cladding layer are p-doped with beryllium.

9. The laser diode of claim 1 wherein said first p-type cladding layer comprises p-AlAsSb.

10. A short-period-superlattice comprising a plurality of alternating layers of either InAs and AlAsSb or InGaAlAs and AlSb lattice-matched to a GaSb or InAs substrate.

11. The short-period-superlattice of claim 10 wherein said layers of AlAsSb are given by the formula AlAs₀.16 Sb₀.84 or said layers of InGaAlAs are given by the formula In_x Ga_y Al_1-x-y As, where x is in the range 0<

x≦

1, y is in the range 0≦

y<

1, and x+y≦

1.

12. The short-period-superlattice of claim 10, wherein said short-period-superlattice is n-type and wherein said plurality of alternating layers comprise either n-InAs and AlAsSb or n-InGaAlAs and AlSb.

13. The short-period-superlattice of claim 12 wherein said plurality of alternating layers comprise n-InAs and AlAsSb and said layers of n-InAs are n-doped with silicon or wherein said plurality of alternating layers comprise n-InGaAlAs and AlSb and said layers of n-InGaAlAs are n-doped with silicon.

14. The short-period-superlattice of claim 12 wherein said layers of AlAsSb or said layers of AlSb are intentionally undoped.

15. The short-period-superlattice of claim 10, wherein said short-period-superlattice is p-type and wherein said plurality of alternating layers comprise either p-InAs and p-AlAsSb or p-InGaAlAs and p-AlSb.

16. The short-period-superlattice of claim 15 wherein said layers of p-InAs and p-AlAsSb or said layers of p-InGaAlAs and p-AlSb are p-doped with beryllium.

17. A method of making a laser diode that operates at mid-wave infrared wavelengths, said method comprising the steps of:

(a) providing an active region having a first surface and a second surface;

(b) providing a first p-type cladding layer contacting said second surface;

(c) providing a second n-type cladding layer contacting said first surface; and

(d) providing said second n-type cladding layer with a plurality of alternating layers of either n-InAs and AlAsSb or n-InGaAlAs and AlSb.

18. The method of making a laser diode of claim 17, comprising providing said first p-type cladding layer with a plurality of alternating layers of either p-InAs and p-AlAsSb or p-InGaAlAs and p-AlSb.