Integrated Optics - Applied Optics Fundamentals and Device Applications - page 264

MOCVD MBE

Flexibility Most compounds and alloys Difficulty with phosphorus and Alloys

with two column V elements

Purity
GaAs

µ 77 139,000 µ 77 125,000

InGaAs µ 300 11,800 µ 300 8,800

InP µ 77 58,900 µ 77 34,000

Photoluminescence
AlGaAs

Comparable to LPE Less than LPE

Others Comparable to LPE Comparable to LPE

Uniformity
Doping

2.5% 2.5%

Thickness 2.5% 1.0%

Composition 0.005 0.005

Interfaces
AlGaAs/GaAs

1-2 Monolayer 1 Monolayer

InAlAs/InGaAs <50 A —

InP/InGaAs — 1 Monolayer

Defect density Dislocation Density 1-3 × 10 3 /cm 2 oval defects

FIGURE 5.28
MOCVD versus MBE—Comparison of Material Properties. (From Dapkus, P.D., J. Crystal
Growth , 68, 345-355, 1984.) [94]

MOCVD MBE

Growth rate and/or
composition

Source temperature (±0.25°C) Source temperature (±0.4°C)

Flow rates (±1%) Substrate temperature (±5°C)

Substrate temperature (±5°C)

Doping Flow rates Source temperature

Substrate temperature Substrate temperature

Purity Source purity Vacuum materials

Growth temperature Source purity

Interface abruptness Reactor design, flow rates, substrate Shutter speed

Rotation speed
Substrate temperature

System cost $200-$400 K $700-$1000 K

Production throughput ≤900 cm 2 /run ≤20 cm 2 /run

Safety considerations Poisonous materials Toxic wastes

Pyrophoric materials
Toxic wastes

FIGURE 5.29
MOCVD versus MBE—Comparison of parameter controls and system cost. (From Dapkus,
P.D., J. Crystal Growth , 68, 345-355, 1984.) [94]