The effects on optical and electric properties of InGaAs(P)/InP MQW structure by Implant Induced Composition Disordering (IICD) and Impurity-Free Vacancy Diffusion (IFVD) are investigated intensively. The experimental results indicate that the band gap blue shift of MQW structure by IICD depends on ion dose and following annealing conditions such as annealing temperature and annealing time. The band gap blue shifts are also influenced by lattice stress. The blue shift of the sample with compressive stress is larger than that of the sample with tensile stress. The band gap blue shift of MQW structure by IFVD depends on the compounds of dielectric layer and the consequent annealing treatment

such as annealing time and temperature. It also depends on the combination between semiconductor cladding layer and dielectric layer. The combination of InGaAs and SiO

2

creates larger blue shift than that of InGaAs and Si

3

N

4

. On the contrary

the combination of InP and Si

3

N

4

creates larger blue shift than that of InP and SiO

2

. The effect of doped dielectric layer has also been investigated. A large blue shift of 224meV is caused by phosphors doped dielectric layer SiO

x

P

y

N

z

. The SIMS characterization indicates that the quantum wells intermixing caused by IICD or IFVD probably is the main reason for the band gap blue shift.