Silicon impurity-induced layer disordering of AlGaN/AlN superlattices

Abstract

Impurity-induced layer disordering is demonstrated in Al0.1Ga0.9N/AlN superlattices grown by metal-organic vapor phase epitaxy. During growth at temperatures as low as 885 °C and under post growth annealing at 1000 °C in N2 the heterointerfaces of Si-doped (Si concentration >8×1019 cm−3) superlattices exhibit layer disordering (intermixing) while the unintentionally doped superlattices remain stable. Shifts in the intersubband energy transitions and scanning transmission electron microscope images showing changes in the layer abruptness are used to verify layer disordering due to Si diffusion in Al0.1Ga0.9N/AlN superlattices.

Enabling area-selective potential-energy engineering in InGaN/GaN quantum wells by post-growth intermixing

“…Our observations demonstrate the feasibility of intermixing in InGaN/GaN QW structure enabled using metal/SiO2 encapsulation, as well as the possibility of having area-selective intermixing. The intermixing mechanism is suggested to be the combination of metal-impurity enhanced interdiffusion and metal/SiO2 stress induced interdiffusion [27][28][29][30]. The latter was supported using a separate experiment based on stress measurements on the capping layers deposited on two separate 4-inch diameter silicon wafers.…”

Formation of Silicon (Si) Grains in AlN Thin Layer Grown on an Si(1 1 1) Substrate: Effect of Deposition Sequence#

“…Furthermore, the diffusion of Si atoms into AlN layers may cause an unintentional doping effect and, therefore, affect the microstructure. 12,[20][21][22][23][24] Studies on the growth of AlN layers are, reportedly, of great interest to research related to the III-nitride compound semiconductors. [25][26][27] However, these studies are still a long way from understanding and controlling the growth mechanism and the microstructural properties of AlN layers, especially, on Si substrate.…”

Selective layer disordering in intersubband Al0.028Ga0.972N/AlN superlattices with silicon nitride capping layer

“…Clearly, the SiN x affects the rate of layer disordering. Since the layer disordering is determined by the diffusion of Si doping within the QWs, 14) the SiN x changes the rate of Si diffusion within the sample.…”

“…Si is necessary for layer disordering, as demonstrated previously. 14) Vacancies, such as column III vacancies (V III ), are more easily created at the uncapped sample surfaces compared to SiN x capped surfaces through the 20 nm AlN capping layer. The Si diffuses along one path with a substitutional mechanism via V III .…”