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GaN Prospects Boosted in IBM Graphene Epitaxy Discovery

Gallium nitride (GaN) offers significant performance benefits for a wide range of analog microchips, from RF-ICs to numerous power control ICs such as high-power HEMTs used in communications, energy, and military applications. GaN is also the material of choice for high-brightness LEDs used in highly energy-efficient solid state lighting.

However, the best-quality single-crystal GaN is grown via several epitaxial processes requiring expensive single-use silicon carbide (SiC) substrates, which has limited its commercialization into broader markets, including consumer electronics. A recent discovery by IBM T.J. Watson Research Center scientists may change all of that, in a single crystal GaN film growth process called direct van der Waals epitaxy.

The compelling research finding has targeted the use of recyclable SiC substrates with graphene overlayers for the growth of GaN films based on the process flow depicted in figure 1. These GaN films were subsequently lifted off carefully without a detrimental impact to their roughness or crystallinity and transferred to silicon-based device structures, which could be processed further for LEDs or ICs. Nickel was deposited on top of the GaN layer, and a thermal release tape technique was utilized for the GaN layer transfer to Si substrate stacks. The recycled SiC substrates were used to fabricate functioning blue LEDs, as shown in figure 2.

Figure 1

Figure 2

Many companies and research groups have tried growing GaN directly on silicon with and without the use of transition layers to reduce the lattice mismatch and defect density on silicon — but with limited success. Even though the lattice match between GaN and graphene is about 23%, the IBM group generated remarkably high-quality epitaxial films that were structurally stable enough for the layer transfer to low-cost, conventional silicon substrate material stacks. In addition, Raman spectroscopy indicated no remnant graphene remained on the back-side of the GaN after the transfer process, and electron microscopy supported that data.

GaN has the potential to replace GaAs in all analog IC devices due to its superior electronic properties, but comparatively high cost has held it back. Many analog IC companies already produce a small percentage of GaN-based RF-ICs, primarily used in military electronics, while GaAs has been favored for more price-sensitive mobile devices such as smartphones.

Most of these companies purchase SiC substrates from Cree, which manufacturers the same chips. So companies such as TriQuint Semiconductor and Texas Instruments are seeking to reduce the conflict of interest in their supply chain reliance on Cree, which is also a top LED producer. Reusable SiC substrates using GaN on graphene may be the answer if this research fully materializes into commercialization over the next five years.

IBM has invested millions into graphene research over the last decade and is considered the leader in this field. It is no surprise that one of its research groups made this discovery, recently published September 11 in Nature Communications by Jeehwan Kim et al. (volume 5, page 4,836). IBM is also interested in developing graphene substrates to replace Si altogether, due to graphene's superior electronic properties over Si. What’s more, the company is planning to invest $3 billion over the next five years in this technology, which will likely lead to more breakthroughs to boost the prospects of graphene and GaN commercialization in advanced electronic devices.

47 comments on “GaN Prospects Boosted in IBM Graphene Epitaxy Discovery

  1. bjcoppa
    October 8, 2014

    For more info on this and related topics, check out author's writing column at http://www.examiner.com/green-business-in-phoenix/brian-coppa which also includes numerous articles on GaN-based LED lighting and power device applications. Feel feel to subscribe for free to receive “new article alerts.”

  2. Davidled
    October 9, 2014

    OLED might use graphene material which will become popular in the computer, mobile phone and any electronic device. The price of graphene will rise up as more graphene is demanded.

  3. etnapowers
    October 10, 2014

    The thermal stability of SiC material might allow a usage of this material to build the LEDs described in this very interesting article.

  4. etnapowers
    October 10, 2014

    The chance to utilize in the same LED devices GaN and SiC structures is very interesting because both of these materials have good features for working at high power ratings and high frequencies. I would explore the possibility of an utilization of SiC together with GaN material due to the particular stability of the SiC material and, I would use it not only as substrate.

  5. bjcoppa
    October 10, 2014

    SiC 4″-6″ wafers cost on the order of thousands of dollars. Thus, this makes them less competitive vs. Si and GaAs which benefit from lower material costs and economies of scale due to higher production volumes for chips. 

  6. bjcoppa
    October 10, 2014

    There is a tremendous savings associated with the multi-purposing and reuse of SiC substrates for multiple device applications, which boosts the prospects for GaN as well since this is one of its most ideal substrates for growing single crystal material with sufficiently low defect densities for device fabrication.

  7. Netcrawl
    October 10, 2014

    @analoging, the growing demand for high speed, high-temp and power handling capabilities have made semiconductor industry rethink upon design and materials used in semiconductors, GaN posses to be a unique material of choice for numerous applications because of its unique characteristics–superior noise factor, high maximum current, high breakdown voltage, high oscillation frequency and power efficient (which requires less heat sink compared to silicon).

  8. Netcrawl
    October 10, 2014

    @etnapowers substantial improvements have been made in material quality for both GaN and SiC over the last few years, we currently see GaN being used primarily for lower power/voltage, high frequency applications and SiC for high power and high voltage switching power applications. SiC has a higher thermal conductivity that GaN, which mean that SiC can theoretically operate at a much higher power densities than GaN or Si, high thermal conductivity combined with wide bandgap and high critical field give SiC semiconductors a great advantage when high power is a key desirable feature.

  9. Netcrawl
    October 10, 2014

    @analoging I believe in terms of cost, GaN on SiC wafers cost about 20 percent more than their SiC counterparts, GaN on silicon wafers promise to be substantially lower cost than SiC on SiC wafers leading to a great deal of current interest in this combination. 

    One important question here is —Can the device structures, thermal performance, reliability and overall benefit of the system cost overthrow or replace the current silicon devices used in today's market?

  10. bjcoppa
    October 12, 2014

    Great comments- following up on the details of this article. SiC has a limited substrate supply chain and only a few providers reducing economy of scale compared to Si so it may take nearly a decade for it to be comparable to Si for many applications.

  11. etnapowers
    October 15, 2014

    “SiC 4″-6” wafers cost on the order of thousands of dollars. Thus, this makes them less competitive vs. Si and GaAs which benefit from lower material costs and economies of scale due to higher production volumes for chips. “

     

    @analoging: I think this is a common fact for new technologies or materials. The costs will decrease, as soon as the production volumes of devices SiC based will be increased, and i guess this will happen relatively soon, due to the good properties of the material in subject.

     

     

  12. etnapowers
    October 15, 2014

    @analoging:  I fully agree with you on this point, the good properties of SiC material make it a really good substrate very compatible with good performing materials like GaN. I think that both of these materials have such properties that could be utilized to create high performance ICs with outstanding performances, provided that the two materials are correctly dimensioned and the structures well designed.

  13. etnapowers
    October 15, 2014

    @Netcrawl: nice post. I think that you're right,  the high power capability of SiC and the high frequency rating of GaN, can be suited to achieve great performances. The designers of the particular IC, which is GaN+SiC based, should manage the power sources and the electric signals properly in order to utilize the good features of these two interesting materials.

  14. etnapowers
    October 15, 2014

    @analoging: I think that this depends on the performances that the ICs built with the new materials will be able to reach. The more good the features will be , the shorter the time frame will be, for a massive adoption of the SiC and the GaN as basic materials for the fabrication of ICs.

  15. bjcoppa
    October 17, 2014

    Thanks for the comments. It is just a matter of cost and time for SiC and GaN-based chips to gain traction in more consumer electronic such as mobile devices. For GaN, it can benefit from non-analogous markets such as LED lighting to boost economies of scale and harness common supply chain elements which are critical for cost reductions.

  16. Netcrawl
    October 18, 2014

    @analoging I agree with you, GaN on LEDs are of particular interest because they have demonstrated much higher performance than traditional lighting technologies and thus offer the potential for major energy savings, using GaN as a substarte holds promise and potential for many industries. GaN on LEDs can withstand higher power densities than diodes made with other substartes, this means a much brighter diode and only one LED light emitter per lamp. 

    According to a recent study conducted by US Department of Energy, applications for GaN substrates have the potential to reduce energy consumption by over 30 percent, those same applications represent potential markets, including laser diodes and even power electronics of over %50 billion.

  17. etnapowers
    October 20, 2014

    @analoging: I agree with you, the GaN is really a key material for the future developments of ICs. The price will decrease as the GaN products will hit massively the market. I guess that also SiC material holds the same promises of GaN, but it's at a more advanced level, many companies are just producing ICs components in SiC, this material is really promising as well as the GaN.

  18. etnapowers
    October 20, 2014

    @Netcrawl: that's very interesting , thank you for this post. Energy efficiency is the winning factor that can represent the reason for the success of GaN material in the fabrication of ICs . The massive adoption of this material will lead to better performances and less pollution , in terms of less material to be recycled and less energy wasting : “this means a much brighter diode and only one LED light emitter per lamp. “
    I think that this material will change electronics and it will impact on our lives positively.

     

  19. PCR
    October 20, 2014

    Very true DaeJ, with the flexible devices there is a high demand for OLED and this is a new trend in the industry which will increase the demand and the prices. 

  20. PCR
    October 20, 2014

    Netcrawl , in the market there is always selection according the quality and prices, I think that the same philosophy is applied hear. 

  21. PCR
    October 21, 2014

    Very true etnapowers, I also do agree with you on this. I believe that always there will be a demand for quality product even thou its expensive than the others. 

  22. ue2014
    October 22, 2014

    Better performance with lesser pollution is a key phrase. Developments & innovations are no use and would not last long if we do not consider the environmental side of it as environmental pollution is going to be one key factor which will be considered in the near future for all proceedings. (Even right now).

  23. ue2014
    October 22, 2014

    I totally agree with your point. Also we need to consider that these innovations are done to help to increase the living standard of people. So many of these would be used in large scale. Therefore, affordability also does matter. As you said very correctly, quality will always comes with a higher price, but we need to consider the other factors as well.

  24. bjcoppa
    October 22, 2014

    Excellent comments, glad to see so many taking the time to consider the ramifications of GaN and SiC technology for energy-efficient LEDs and high power defense communications. The US DOE and DOD have been funding these materials for over a decade so that the US takes the lead for strategic military applications.

  25. bjcoppa
    October 22, 2014

    You are correct in stating the cost reduction associated with increased brightness and efficiency of the LEDs leads to less LEDs being needed per lamp which can range up to $2-4 per LED in reduced cost for a lighting system.

  26. bjcoppa
    October 22, 2014

    LED lighting is a no-brainer compared to other lighting alternatives when it comes to energy-efficiency. That is why many national governments have spent billions subsidizing R&D and manufacturing globally, especially in places like Taiwan and So. Korea. A conversion to LED lighting is just another way to reduce carbon emissions and reduce dependence on foreign oil which is beneficial to the environment.

  27. bjcoppa
    November 4, 2014

    Amid the selling of IBM's chip business to Global Foundries, they will now acquire this technology which will kept in the R&D stage for several years before finding relevant applications in high-end chips. A first landing spot is more likely in defense-related RF ICs or HEMTs on a low volume scale for a narrow range of applications.

  28. uchiha
    November 4, 2014

    @ue2014: Good point, but what do you mean by other factors ? I know that we cannot always consider the price because as you said quality comes with a price tag but balancing both is something which we can always consider. 

  29. ue2014
    November 5, 2014

    @uchiha – yes, balancing both would be ideal. What I meant by other factors also same. We need to look at what kind of applications will these would be used and affordability and suitability of the price for the usage and situation.

  30. etnapowers
    November 6, 2014

    @Ranasinghe: that's absolutely true, that's the main reason for why high value products are sold massively on the market despite of their price. The added value justifies the increased cost of an object.

  31. etnapowers
    November 6, 2014

    @ue2014: we're on the same page. The electronics business has not only to be focused on the profit, but also on the real improvements on the lives of the consumers. This trend adds value to what electronics engineers do every day in the industry sector to create systems that effectively make our life easier, safer, comfortable, by not impacting excessively the environment.

  32. etnapowers
    November 6, 2014

    @ue2014, you're correct, many times a good sustainable business model leads to an improvement of quality of the environment in which we all live and finally this process leads to a better consciousness of human presence on the earth.

     

  33. etnapowers
    November 6, 2014

    That's a simple consideration, that may lead to a process of production of high efficiency LEDs more brilliant and less power consuming. This will maximize the gain profit for a LEDs based system.

  34. etnapowers
    November 6, 2014

    “A conversion to LED lighting is just another way to reduce carbon emissions and reduce dependence on foreign oil which is beneficial to the environment.”

     

    That's the main reason for why LED lighting should be adopted massively by all the governments that are interested in reducing the pollution and increase the quality of the air, that the people breath.

  35. bjcoppa
    November 12, 2014

    Check out a related electronics tech column of the author of this article at: www.examiner.com/green-business-in-phoenix/brian-coppa & subscribe for free article alerts for new posts. Comments are welcome in both columns and author can be reached via Twitter direct messages at: twitter.com/alternativenrgy .

  36. PCR
    November 22, 2014

    True ue2014, affordability is a factor only for the one segment in the market. But What I am saying is always there is a marker for hi quality products in the market thou it is expensive. 

  37. chirshadblog
    November 23, 2014

    @ranasinghe: Do you really think so ? Even with the current situation ? 

  38. PCR
    November 23, 2014

    Exactly etnapowers, sometimes the features added to the basic products a value added feature will take over the basic need of the product.  Smart phone market is the best example  for that it is no more only a  communication devices. 

  39. ue2014
    November 24, 2014

    @Ranasinghe – Agree with you. Quality Products will definietly have a demand in the  Market. Even the segment that you are talking about which are sensitive to affordability also now tend to be more concern about quality of what they purchase too. 

    Also what I suggested was that we need to be vigilant about the usage of the product (May be the Frequesncy & situation) with the affordability too. I.e. If its a product that will be used in day to day life or applicable to all consumer layers, then affordability does matter. 

  40. Davidled
    December 1, 2014

    Today, all electronic device used everywhere consumes less and less power with better performance, compared with it over the decade ago. In the future, this trend could be continued. In addition, other harvest energy source will be continously developed and improved.

  41. etnapowers
    December 12, 2014

    @Ranasinghe: that's absolutely correct. The trend of future devices is determined by the choices of the producers of today. If the electronics has a positive impact on the environment, reducing pollution , the effects may not be immediately visible , but on the long term these choices will make our environment less polluted and finally our lives will be better in terms of health and quality.

  42. etnapowers
    December 15, 2014

    @DaeJ: I agree with you, and I add that saving energy is very important in electronics , another key factor is the efficiency of conversion of energy and the capability to store and manage effectively the harvested energy.

  43. PCR
    December 16, 2014

    And on the other hand etnapowers, we have to think about our health again and again cause that now a day's every things getting easy and easy thanks to technology which will lead to have less exercise for the physical body. 

  44. PCR
    December 16, 2014

    Very true etnapowers, energy consumption is the factor which will decide the sustainability of the gadget in the market. 

  45. etnapowers
    December 18, 2014

    Agreed. The sedentarity is a risk for the health of the habitants especially in the rich countries. I think that electronics might improve our quality of life also by facilitating our physical activity, by mean of wearable sensors for sport activities. A good balance between conforts and physical activity would be the optimum. Electronics may enhance both of the above aspects.

  46. etnapowers
    December 18, 2014

    “Very true etnapowers, energy consumption is the factor which will decide the sustainability of the gadget in the market. “

    Ranasinghe: I couldn't agree more with you. “sustainability” is the key concept not only in terms of figure of efficiency and economic profitability of an object.
    An object having high efficiency will avoid a wasting of the energy for all his time of utilization, this efficiency on the long term will be positive for the whole energy distribution net, which will be working with an excellent performance.

     

  47. jessepkm
    August 12, 2017

    It's a shame the GaN have a high cost, but I believe that with the investment of 3 billion IBM will be able to find a way to reduce the costs through new variations of compounds in conjunction with the Graphene.

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