Semi-insulating indium phosphide (formula: InP) wafer at prime grade for sale is dark gray crystal with a bandwidth (Eg=1.35 eV) at room temperature, a dissociation pressure of 2.75MPa at a melting point, an electron mobility of 4600cm2/(V·s), and a hole mobility of 150cm2/(V·s). PAM-XIAMEN uses VGF process to ensure the purity of the material. All of our substrates are precisely polished and protected by a protective atmosphere, meeting the requirements of Epi-ready usage. PAM-XIAMEN can provide various sizes, crystal orientations, polished, doped and customized prime grade InP wafers with semi-insulated type.
1. Semi-insulating Prime Grade Indium Phosphide Single Crystal Wafer Specification
|Conductivity type / Dopant:||SI / Fe|
|Primary Flat Orientation:||(0-1-1)|
|Primary Flat Length:||16±1 mm|
|Secondary Flat Orientation||(0-11)|
|Secondary Flat Length:||7±1mm|
|Laser Mark:||Back side major flat|
|Edge Rounding:||0.25(Conform to SEMI Standards)mmR|
|Surface:||Side 1:Polished Side 2:Etched|
|Package:||individual container filled with N2|
|Remark:||Special specifications will be discussed separately|
Note: The X-ray system is used for precise orientation, and the indium phosphide orientation deviation is only ±0.5°. The wafer of indium phosphide at prime grade is polished by chemical mechanical polishing (CMP) technology. Prime grade InP wafer surface roughness is <0.5nm.
The flat position of indium phosphide substrate is shown as following diagram:
2. Difficulty for Growing High Quality Semi-insulated Indium Phosphide
Usually, the semi-insulation indium phosphide single crystal wafer form the indium phosphide foundry is prepared by doping iron atoms during single crystal growth. In order to achieve the semi-insulation, the doping concentration of iron atoms is relatively high, and the high concentration of iron is likely to diffuse with the epitaxy and device process. Moreover, because the segregation coefficient of iron in indium phosphide is very small, the indium phosphide single crystal ingot exhibits an obvious doping gradient along the growth axis, and the iron concentration at the top and bottom differs by more than one order of magnitude. Therefore, the consistency and uniformity are difficult to guarantee. For a single indium phosphide wafer that is cut, due to the influence of the solid-liquid interface during growth, iron atoms are distributed concentrically from the center of the monocrystalline InP wafer outward, which obviously cannot meet the needs of some device applications. All these factors are currently the biggest obstacles restricting the production quality of semi-insulating indium phosphide single crystal wafers.
3. Solutions for Improving the Prime Grade Semi-insulating InP Wafer Quality
In recent years, research at home and abroad has shown that the semi-insulating InP substrate obtained by high-temperature annealing treatment of low-resistance non-doped InP wafers in a certain atmosphere can overcome the above-mentioned problems. In InP crystals, the formation mechanism of semi-insulating can be roughly summarized into two aspects:
One is to realize the semi-insulating state by doping deep host (element) to compensate shallow donors. The original iron-doped semi-insulating indium phosphide belongs to this;
The other is to reduce the concentration of shallow donors through the formation of new defects, and at the same time the resident deep host (element) is compensated. Non-doped semi-insulator single crystal InP substrate belongs to this category. Defects can be formed during high-temperature annealing and irradiation.
According to this idea, the researchers from PAM-XIAMEN have prepared the SI single crystal InP wafer at prime level by annealing in an iron phosphide atmosphere not only have fewer defects, but also have good uniformity.
As a new type of semi-insulating wafer, prime grade indium phosphide is of great significance for improving and enhancing the performance of InP-based microelectronic devices. The semi-insulating indium phosphide wafer prepared by the high-temperature annealing process maintains the high resistance characteristics of the traditional primary iron-doped InP substrate. At the same time, the iron concentration is greatly reduced, and the electrical properties, uniformity and consistency of the prime grade semi-insulating indium phosphide are significantly improved.