OXFORD INSTRUMENTS

Product Info:

ICP & ALE for p-GaN HEMTs

• ICP etch for bulk of GaN layer
• ALE allows accurate etch control of remaining GaN/AlGaN
• ALE provides “soft-landing” onto AlGaN surface after GaN ICP etch
• Low damage, surface smoothing with ALE

Precise control of p-GaN etch depth with minimum damage on AlGaN surface is needed for higher performance E-mode HEMT devices with higher drive current, lower off-leakage and improved dynamic on-resistance.¹

 (left) 50% reduction in AlGaN roughness with ICP & ALE process 0.4 nm (Ra) – OI data

¹Zheng et al, High Selectivity, Low Damage ICP Etching of p-GaN over AlGaN for Normally-off p-GaN HEMTs Application, Micromachines 2022,13, 589.

Partially-recessed gate MISHEMT - ALE with Etchpoint™ for Precise AlGaN Thickness

• ALE with Etchpoint utilised for precise AlGaN etch accuracy with 5 ±0.5 nm remaining AlGaN thickness
• Implemented in fabrication of partially-recessed gate MISHEMT

In-situ reflectance end-pointing perfectly correlates with TEM measurements

ALE for interface optimisation

• Optimised endpoint detection (EPD) for GaN HEMT Etching
• Atomic layer etch for low, damage accurate etch control of AlGaN
• Optimised patent-pending UV wavelength endpoint control for ±0.5 nm accuracy

 
Fully-integrated LayTec EPD with Oxford Instruments PlasmaPro 100 Cobra ALE system

Remote plasma ALD

• Large area (200 mm) remote CCP plasma
• Low damage and uniform across 200 mm
• Small chamber volume
• Designed for high-volume manufacturing

Plasma ALD nitridation to remove Ga-oxide: In-situ pre-treatment of GaN surface

In-situ plasma pre-treatment reduces interface defects (Dit) for improved GaN HEMT efficiency

• High-quality plasma ALD Al₂O₃ films deposited
• >7 MV/cm breakdown
• >7000 WPM throughput for 20 nm Al₂O₃
• Optimised NH₃ plasma pre-treatment for GaN HEMT validated with device characterisation
• Gate passivation by plasma ALD of Al₂O₃ results in superior electrical performance
• Pre-treatment and ALD performance is production qualified
• High-quality Al₂O₃ deposited by remote, low-damage plasma ALD with low CoO
• Breakdown of >8 MV/cm with low leakage current and low hysteresis

Process Stability (during demo runs)

# of wafers

Our OIPT SiC applications

1. SiC plasma polish: A dry polish solution to prepare Epi-ready SiC and frontside processes for power applications

• Preferential etching of damaged area.
• Effectively leaving behind good crystal structure and approx. 50% R_a reduction.
• Subsurface damage free surface with some leftover waviness

2. Trench etch: Can achieve rounded corners (reduce field crowding), smooth sidewalls, no microtrench, high selectivity, high aspect ratios (HAR)

 High selectivity

 HAR

3. Plasma ALD & ALE for interface optimisation: To improve reliability of power devices by surface smoothing and interface optimisation (less charge trapping/defects at multiple interfaces throughout the device)

Plasma ALD

• Low deposition temperature
• Wafer-scale uniformity
• High growth rates
• Surface pre/post-treatment
• Improved film properties

Plasma ALE

• Cyclic etch process.
• Self-limited steps.
• Process operates at very low bias for minimum damage.

Example: Work done with University of Warick - using ALE and ALD to improve Dielectric-SiC interface

• Prepare trench surface using ALE/ plasma pre-treatment (OI process used for this work).
• ALD dielectric (OI process used for this work).

3” Wafer Marathon Data - Waveguide Process (Cl₂/Ar)

• Average number of particles added: 0.1 particles/cm², > 0.5 µm. (average rate = 0.52 um/min)
• Mechanical clean after 500 µm of InP etch as end of marathon was reached
• Repeatability = +/- 2.2 /%

3” Wafer Marathon Data - Waveguide Process (CH₄/H₂/Cl₂)

• Average number of particles added: 0.3 particles/cm2, > 0.3 µm ((average rate = 1.45 um/min)
• Mechanical clean after 240 µm of InP etch
• Repeatability = +/- 2.0 /%

Hot ESC 

Oxford Instruments has launched an innovative, newly designed hot ESC, that, after extensive testing at HVM customer facilities producing InP optoelectronic devices. The reliability of the resistively heated design (no hot oil), as measured by heat-cool cycles until component failure, has been significantly extended to deliver MTBF rates that are consistent with the requirements of HVM InP device manufacturers. It is an automated 6-inch wafer process with cross wafer uniformity of less than ±3%. In addition, the newly designed hot ESC has the capability to exceed the typical upper limit of processing temperature, which widens the process window to optimise ridge etch surface characteristics like smoothness, and micro-trench reduction by up to a factor of 10. Operating temperature range from 120 °C – 210 °C (250 °C optional)

Initial process results on 6”wafers using

• Cl₂/Ar chemistries
• Full automation process
• 150 mm ESC, max at 210 ºC

Cost of Ownership

• Mean Time To Clean (MTTC): < 8 hours

• Mean Time Between Failures (MTBF): > 250 hours
• Mean Time To Repair (MTTR): < 6 hours
• Mean Time Between Clean  (MTBC): > 300 RF hours
• Throughput 2095 wafers per month (24/7 operation 95% uptime)
• <10% chamber to chamber matching
• Minimum particle size: 0.3-1.2µm
• >30 particle adders
• We have work closely with our customers to refine CoO model and minimise cost per wafer
• Endpoint detection
  • Laser interferometry
  • Optical Emission Spectroscopy (OES)

General images from processes

 Grating for DFB laser

 Ridge waveguide etch for InP laser

 Vertical profile etch for InP facet

 Sloped mesa for InP photodiode

witec360 Semiconductor Edition is a high-end confocal Raman and photoluminescence (PL) microscope specifically configured for the chemical imaging of semiconducting materials. It helps researchers accelerate the characterization of crystal quality, stain and doping in their semiconductor samples and wafers.

The microscope’s extended-range scanning stage enables the inspection of up to 12-inch (300 mm) wafers and the acquisition of large-area Raman images. It is equipped with vibration damping and active focus stabilization to compensate for topographic variation during measurements over large areas or long acquisition times. All microscope components are fully automated, permitting remote-control and the implementation of standard measurement procedures.

Benefits

• Full inspection of up to 300 mm (12 inch) wafers
• Non-destructive characterization of crystallinity, polymorphism, defects, strain and doping
• Analysis of wide-bandgap semiconductors and layered structures
• Surface analyses, depth scans and 3D imaging

Key features

• Industry-leading confocal Raman and PL microscope for high speed, sensitivity and resolution – simultaneously
• Scientific-grade, wavelength-optimized spectrometer for high signal sensitivity and spectral resolution
• Large-area scanning (300 x 350 mm) for wafer inspection
• Active focus stabilization for large-area measurements (TrueSurface)
• Vibration damping
• Extensive automation for remote-control and recurring measurement workflows
• Software for advanced data post-processing

Next-Generation AFM Design Delivers the Highest Performance of Any Large-Sample AFM

• Jupiter Discovery achieves ultra-high resolution and scan rates 5-20× faster than other AFMs, setting a new performance benchmark for large-sample AFMs.

Optimized Workflow Provides a Simpler and More Productive User Experience

• Pre-mounted probes, a unique side-view camera, and exclusive FFM Topography imaging mode with Autopilot enable new users to go from sample loading to results in mere minutes.

Unmatched Configurability Provides the Versatility to Meet the Needs of Any Research Group

• A vast selection of accessories and capabilities enables multidisciplinary research, while configuration options help span a wider range of research budgets.