Samples structure

Growth Parameters

Substrate

P type Si (111)

T_subs = 850˚C, T_Al = 1127˚C, Δt = 30 seg.

First Film

AlN

T_subs = 850˚C, Plasma N (Power = 150 W, 0.025 sccm)

Δt = 22 min. T_subs = 850˚C, T_Al = 1127˚C Δt = 30 seg.

Second film

GaN

T_subs = 800˚C, T_Ga = 993˚C, Power = 150 W, 0.025 sccm, Δt = 2 h 3 min.

Substrate

1 μm of GaN grown on Al₂O₃ by MOCVD

First film

GaN

T_subs = 880˚C, T_Ga = 972˚C, Plasma N (Power = 150 W, 0.025 sccm), Δt = 1 h

Second film

AlN

T_subs = 850˚C, Plasma N (Power = 150 W, 0.025 sccm), T_Al = 1046˚C, Δt = 30 seg.

Third film

InGaN

T_subs = 880˚C, T_In = 700˚C, T_Ga = 972˚C, Δt = 25 min.